Principles of Engineering

Glossary

ABET, Inc.: Accreditation Board for Engineering and Technology Standards. 
Abrading: The process of removing material by applying friction
Abutment: The part of a structure (as an arch or a bridge) that directly receives thrust or pressure.
Acceleration: Exists when the velocity of a particle changes with time.
Acceptance level: The maximum number of defects in a sample that will permit acceptance of the entire lot.
Accumulator: A device (as in a hydraulic system) in which a fluid is collected and especially in which it is kept under pressure as a means of storing energy.
Accuracy: Degree of conformity of a measure to a standard value. 
Acoustical: Of or relating to the sense or organs of hearing, to sound, or to the science of sounds.
Actuator: A device that transfers fluid or electrical energy into mechanical energy.Adhesion: The process of fastening two parts by the application of a third material such as glue, epoxy, etc. 
Allowable Stress: Level of stress judged to be permissible in a design.
Alloy: A substance composed of two or more metals or of a metal and a nonmetal intimately united usually by being fused together and dissolving in each other when molten. 
Alternator: An electric generator for producing alternating current
Analog: Of, relating to, or being a mechanism in which data is represented by continuously variable physical quantities
Angle: The union of two co-planar rays intersecting at a common endpoint.
Annealing: The process of softening metal for improved machinability or cold working by heating it to its critical temperature, holding it there until the temperature is uniform, then cooling it slowly at a controlled rate.
Arch Bridge: a bridge that uses long span arches for support”
Assembly: Consisting of individual parts fitted together to create a final product
ASTM: American Society for Testing and Materials
Attribute Listing: idea generation listing and combining the attributes associated with a situation.
Austenite: a solid solution in iron of carbon and sometimes other solutes that occurs as a constituent of steel under certain conditions
Automation: A machine or system that operates with minimal human control: using automated machines as control for production.
Axial Force: Force aligned along the central axis of a material. 
Bar Chart: A graph in which the data is represented by horizontal or vertical bars.
Beam Bridge: A bridge whose main structural element consists of a beam set across two or more vertical supporting members.
Bearings: Devices used to reduce friction between rotating shafts and fixed carriers. Examples are roller, ball, and air bearings.
Belt: A continuous band that transmits motion from one pulley to another.
 Benchmark: A point of reference for making measurements or judgments.
Bernoulli’s Law: A change in the velocity of a fluid caused by a constriction produces an opposite change in pressure.
Blow Molding: Method of fabrication in which a warm plastic parison (hollow tube) is placed between the two halves of a mold cavity and forced to assume the shape of that mold cavity by use of air pressure.
Bonding: Adhering materials with cement or glue
Boyle’s Law: The volume of a gas at a constant temperature is inversely proportional to its pressure.
Brainstorming: A group problem-solving technique that involves the spontaneous contribution of ideas from all members of the group; during this process, ideas are shared but not critiqued.
Brazing: Sometimes called hard soldering. Joining pieces of metal together below the point of fusion by melting a third
British Thermal Unit (BTU): The US Customary unit of thermal energy; the amount of energy needed to raise the temperature of one pound of pure water by one degree Fahrenheit.
Brittleness: The description for a material which is neither ductile nor malleable and will fail suddenly without warning.
Broaching: a precision machining process used to change the shape of a hole into another shape (e.g. a square or keyhole); a broach is used to do this (see pictures below)
 Bronze Age: The period of ancient human culture characterized by the use of bronze that began between 4000 and 3000 B.C. and ended with the advent of the Iron Age.
Buckling: Failure caused by bending, giving way, or crumpling due to excessive force
CAD: computer-aided design; drafting or solid modeling performed on a computer.
Cadmium Sulfide Cell: A light sensitive resistor; also known as a photocell.
CAM: computer-aided manufacturing; aiding in the manufacturing process through the use of computer technology.
Cp: Capability Index, a measure of how capable a machine or process is to stay within the limits given for that process or machine.
Cable-stayed Bridge: A bridge in which the deck is supported on either side of a central tower or towers by cables. Unlike a suspension bridge, the cables that hold the deck attach directly to the tower, rather than hanging from a larger cable running between the towers.
 Calendaring: The process of forming plastic sheets by squeezing a thermoplastic material between a series of rollers.
Caliper: any of various measuring instruments having two usually adjustable arms, legs, or jaws used especially to measure diameter or thickness -- usually used in plural <a pair of calipers> (0) see example of dial caliper below.
Calorie: A metric unit of thermal energy; the amount of energy needed to raise the temperature of one gram of pure water by one degree Celsius; A Calorie (capital C) is a “food calorie” and is 1000 calories); 1.00 calorie = 4.186 Joule.
Cam: A mechanical device used to change simple rotary motion into a more complex motion.
Cam Cycle: one complete 360º rotation of a cam
Carbide: A compound of carbon with one or more metallic elements.
Carbon: A nonmetallic chiefly tetravalent element found native (as in the diamond and graphite) or as a constituent of coal, petroleum, and asphalt, of limestone and other carbonates , and of organic compounds or obtained artificially in varying degrees of purity especially as carbon black, lampblack, activated carbon, charcoal, and coke (Webster.com)
Carburizing: (Cementation) Adding carbon to the surface of iron-base alloys by absorption through heating the metal at a temperature below its melting point in contact with carbonaceous solids, liquids, or gasses.The oldest method of case hardening. 
Case Hardening: Carburizing and subsequently hardening by suitable heat-treatment all or part of the surface portions of a piece of iron-base alloy.
Case study: A broad-based analysis of an engineering problem.
Casting: The process of producing an object by pouring a heated liquid material into a mold and allowing it to solidify by cooling.
Catapult: A system used to launch objects. (Ancient catapults used bent wood as the power source, modern systems use power such as steam.)
Cell: A single space for an entry in a spread sheet
Center of Gravity: The point at which the entire weight of a body may be considered as concentrated so that if supported at this point the body would remain in equilibrium in any position.  Same location as center of mass.
Center of Mass: The point in a body or system of bodies at which the whole mass may be considered as concentrated.  Same location as center of gravity.
Centi: a prefix meaning one hundredth or 1/100 or 102; symbol: c
Centroid: A point whose coordinates are the averages of the corresponding coordinates of a given set of points and which for a given plane or three-dimensional figure (as a triangle or sphere) corresponds to the center of mass of a thin plate of uniform thickness and consistency or a body of uniform consistency having the same boundary.
Cementite: A compound of iron and carbon known as “Iron Carbide,” which has the approximate chemical formula Fe3C containing 6.69% of carbon. Hard and brittle, it is the hard constituents of cast iron, and the normal form in which carbon is present in steel. It is magnetizable, but not as readily as ferrite.
Center Line: A line consisting of a long dash followed by a short dash, that is used to show and locate centers of arcs and circles, and to describe the center axis of cylindrical forms.
Ceramic: A compound of metallic and nonmetallic elements, for which the interatomic bonding is predominantly ionic.
Chain: A continuous band consisting of metal or plastic links that transmits motion from one sprocket to another.
Charles’ Law: The volume of a gas at a constant pressure is directly proportional to its temperature.
Chart: A sheet or map giving information in the form of a table, list or diagram
Chemical: Of, relating to, used in, or produced by chemistry.
Chemical energy: The energy associated with chemical bonds and bonding structure. This includes the energy associated with changes in phase from solid to liquid to gas. Chemical energy does not lend itself to an equation. Rather, there are tabulated values associated with all known elements and compounds, as well as values for the most common chemical reactions. 
Chronological:  Arranged in or according to the order of time.
Circle: A closed curve with coplanar points at the same distance from the center point.
Class of Fit: Fits are arranged in three general groups known as running and sliding fits, locational fits, and force fits
Closed loop: The output of a process is constantly monitored and the input adjusted according to feedback provided by sensors.
Cohesion: The process of fusing two like materials for the purpose of fastening. Examples include friction welding, spot welding, electron beam welding and laser welding).
Cold forming: The process of working metal into shape below the temperature of recrystallization. Cold forming improves the strength; machinability, dimensional stability, and surface finish of metals.
Communication: The act of transmitting useful data or ideas to one or more receivers; can be one-way or two-way.
Component: A single device or part in an assembly
Component Relational Sketch: A pictogram showing the relationship of how the components react together in a system.
Composite: A multiphase material formed from a combination of materials that differ in composition or form, remain bonded together, and retain their identities and properties.
Compound: A substance of two or more elements in fixed proportions. Compounds can be decomposed into their constituent elements.
Compression: The effect of a force which tends to shorten an object in the direction of the force. Such a force is called a compressive force, and the object it acts on is said to be in compression. For example, the towers of a suspension bridge are in compression.
Compression molding: A forming process in which a powdered thermosetting plastic is placed in a heated mold cavity then compressed by a ram. After being compressed, the plastic solidifies, the ram retracts, and the part is ejected.
Compressor: A device that converts mechanical force into pneumatic energy.
Computer aided drafting (CAD): The use of a computer to create drawings
Computer Numeric Control (CNC): A combination of a computer, a digital control system, and a machine tool that enables the machine to accept standard codes and automatically make parts.
Concurrent: Occurring at the same time; running parallel; acting in conjunction.
Conditioning: The process of treating a material to achieve physical, electrical, or mechanical properties.
Conduction: (Thermal definition) The transfer of heat energy by physical contact.
Conflict Of Interest: Moral dilemma from dual responsibilities or loyalties.
Contour: An outline, especially of something curved or irregular.
Constraints: Restrictions or guidelines.
Contribution: To supply a significant part.
Control Limits: (Lower and upper control limits (LCL and UCL)); these describe what the process is actually giving you; they are random variables that are a function of the process itself; they are observed or calculated, not set.
Convection: The transfer of heat energy by moving a heated substance from one place to another.
Conveyer: A belt like device used to move objects.
Coplanar: Occurring in the same plane.
Counter bore: A larger drilled hole concentric with a smaller diameter hole. The larger hole is not as deep as the smaller hole.
Countersink: A beveled or conical surface at the top of a drilled hole for the purpose of accepting a bolt head.
Coupling: A system used to connect and transfer energy from one part to another - usually shafts that rotate.
Crankshaft: A shaft that has journals which changes reciprocating motion to rotary motion.
Creep: The slow change of dimensions of an object from prolonged exposure to high temperature or stress. 
Critical Component: A component in a system that, if it fails, renders the entire system useless. In reliability studies, Critical Components are the focus of improvement efforts.
Critical temperature (points): Temperatures at which internal changes or transformations take place within a metal either on a rising or falling temperature.
Crystalline: In some resins a state of molecular structure denoted by uniformity and compactness of the molecular chains. This characteristic is attributable to the existence of solid crystals with definite geometric form.
Current: The total amount of electrons flowing through a circuit per unit time; measured in Amperes (one coulomb of electrons passing a single point per second).
Data: Information (measurements or statistics) used as a basis for reasoning, discussion, calculation or transmission.
Data base: 1) Collection of similar information in a computer file; a data base can be divided into records and fields; 2) A facility which is a central point for the collection and dissemination of various types of information.
Deflection:  A measure of deformation of a structure due to applied loads.
Deformation: Change in size and/or shape of a body due to stress.
Delphi Technique: Individuals contribute solution ideas independently to a central office.
Delta: Greek letter used in mathematical formulae to represent change.
Density: Mass per unit volume.
Design: Translation of a concept into a satisfactory, producible, salable form.
Design brief: A format for stating a design problem.
Design Constraints: Requirements and limitations under which the design process takes place.
Desktop Publishing: Creating and publishing a document using a PC and output device such as a laser printer.
Destructive Testing:  Material or product testing in which information is learned about the material/product via careful measurements and recordings as the material/product is destroyed.
Detail: Shape or feature on a model.
Deviation: The difference between the actual measurements of a product and the design specifications.
Diagonal: A line that is slanting or oblique
Dial Indicator: A precision measurement device accurate to at least one thousandths of an inch used to measure inside and outside dimensions and depths of materials with the output being read using a dial.
Diaphragm: Part of a pump that consists of a flexible membrane.
Digital: An information system whose signals have only two states, 1 (closed) or 0 (open).
Dilemma: A choice between equally unpleasant courses of action.
Dimension Line: Thin line segment capped on the ends with arrowheads, that indicate the length of the dimension.
Dimension: Numerical value used on a drawing to describe location, size, shape, or geometric characteristic.
Dimensioning: The process of placing measurements and notes on a drawing to completely communicate its meaning.
Dimensional: A measure in one direction; specifically: one of three coordinates determining a position in space or four coordinates determining a position in space and time.
Discipline: An area of study
Displacement Diagram: (Re: cams) A drawing that represents the desired motion of the cam. The length of the diagram is equal to the circumference of the working circle. The height of the diagram is equal to the radius of the working circle. The length of the diagram is divided into intervals representing degrees of rotation of the cam, a common interval would be 30 degrees. The smaller the interval, the more accurate the cam profile:
Displacement: Movement of an object through a distance. 
Drilling: To bore or drive a hole in. A machining process that produces a hole (0)
Ductility: Property of materials that will undergo plastic deformation or elongation of more than 5% before fracture.
Dwell: That segment of cam rotation that causes the follower to remain stationary
Dynamics: The behavior of matter when in motion; (physics) the study of why objects move.
Eccentric: A device that rotates in an off-center position on an axle or shaft. 
Edge: The line where two surfaces or points intersect.
Elastomers: Any of various elastic substances; An amorphous, cross-linked high polymer that will stretch rapidly under tension, reaching high elongations (500 to 1000%)
Electron Discharge Machining (EDM): A separating process that produces a spark between an electrode and the work piece causing an erosion action. This process can only be used on electrically conductive materials.
Elastic Modulus (Young’s Modulus or the Modulus of Elasticity): The ratio of stress to strain when deformation is totally elastic; also a measure of the stiffness of a material.
Elastic Potential Energy: The energy that can be stored in the compression or extension of an elastic material (traditional springs included). The equation for the energy stored in a spring is SE= ½  kx2  where “k” is the spring constant (or modulus of elasticity for a solid ) and “x” is the distance of extension or compression.
Electromagnet: A core of magnetic material surrounded by a coil of wire through which an electric current is passed to magnetize the core.
 Electromagnetic energy: The energy associated with electricity, magnetism, and electromagnetic waves.
Elastomer: A polymeric material that may experience large and reversible elastic deformations.
Electrical: Of, relating to, or operated by electricity.
Electrode: A conducting element that emits or collects electrons or ions or controls their movement.
Electronic: The use of electronics to control a system or machine.
Element: A substance that cannot be decomposed into simpler substances by chemical means.
Ellipse: The group or set of all points in the same plane whose sum of distances from two points (foci) is constant. An ellipse looks like a squashed circle or a circle viewed at an angle.
Engineering: A course of study followed by a professional career that involves complex analysis, design, and development of solutions to technical problems.
Engineering technology: A course of study followed by a professional career that involves testing, troubleshooting, servicing, and maintenance of technical product sand systems.
English system: (U.S. Customary System) A measurement system in which the fundamental units are the foot, slug, and second.
Environment: The ecological community that one lives in
Equilibrium: A state of balance due to the equal action of opposing forces in a structure.
Essence: The quality or nature of something that identifies it or makes it what it is.
Ethics: a. a set of moral principles or values b. a theory or system of moral values <the present-day materialistic ethic> c. plural but singular or plural in construction : the principles of conduct governing an individual or a group <professional ethics> d. a guiding philosophy.
Eye Contact: Visual contact with another person's eyes
Experimentation: Developing a solution by conducting experiments and gathering information.
Extension Line: Thin lines used to establish the extent of a dimension.
Extrusion: A forming process which uses force to push material through a die to give it a specific cross sectional shape.
Factor of Safety (FOS): The ratio of ultimate or yield stress (depends on the material and standards people use) to allowable stress.
Failure: A fracturing or otherwise not performing due to stress or outside events.
Fall: (Re: cam) That segment of cam rotation that causes the follower to move downward.
Fatigue: The failure or decay of mechanical properties after repeated applications of stress. Fatigue tests give information on the ability of a material to resist the development of cracks (which eventually bring about failure) as a result of a large number of cycles.
Fastening: The joining of two or more parts or materials through the application of mechanical devices, adhesive materials or a cohesive process.
Feature: Any physical portion of an object, such as a hole or fillet.
Ferrite: any of several magnetic substances that consist essentially of ferric oxide combined with the oxides of one or more metals (as manganese, nickel, or zinc), have high magnetic permeability and high electrical resistivity, and are used especially in electronic devices.
Ferrous: Related to iron (derived from the Latin ferrum); iron base alloys.
Free Fall: Where an object moves freely under the influence of gravity
Freehand: Done without the use of tools or drawing equipment.
Filter: A component used to remove impurities from air or liquids.
Finishing: The final processes applied during the production or a part. (examples include coating, de-burring, blast finishing, coloring, cleaning, etc.)
Firing Angle: The angle in between the horizontal and the initial velocity vector of a projectile
Flame Hardening: A process of hardening a ferrous alloy by heating it above the transformation range by means of a high-temperature flame, and then cooling as required.
Fluid: The medium used to transfer power can be a liquid or a gas. 
Force: A push or pull exerted by one object on another.
Forging: The working of a piece of metal into a predetermined shape by applying pressure or impact blows. Forging increases the strength of a part by compressing and aligning the surface to the shape of the die. 
Fracture: The act or process of breaking or the state of being broken.
Free Body Diagram: A sketch of an object (body) of interest with all the surrounding objects stripped away and all of the forces acting on the object (body) shown.
Frequency distribution: The number of times that a certain characteristic occurs and is represented using a histogram.
Friction: A force that opposes the motion or intended motion of a body in contact with another body.
Fulcrum: The support structure around which a lever rotates. See lever.
Gage blocks: Accurately ground and polished blocks of steel, measured to one millionth of an inch, and used as standards for measurements
Gear: A wheel with teeth that will allow the transfer of power when coupled to another gear.
Gear trains: A set of gears used to transmit power, change output direction, or change speed or force.
Gender Bias: A settled or prejudicial outlook towards males or females.
Generator: A device that converts mechanical energy to electrical energy.
Grains: Individual crystals in metals.
Grain size: Average diameter of grains in the metal under consideration, or alternatively, the number of grains per unit area.
Graph: A diagram illustrating, by use of points, lines, line segments, or curves, the relationship between variables.
Graphics: A graphic representation (as a picture, map, or graph) used especially for illustration.
Gravitational Potential energy: The energy stored by an object’s position in a gravity field. On or near the surface of the Earth, PE = mgDh where “m” is the object’s mass, “g” is the Earth’s gravitation constant, and “Dh” is the change in height the object undergoes or has the “potential” of undergoing.
Gravity: A fundamental physical force between any two objects in the universe; as applied to the earth, the force that is responsible for the weight of objects.
Ground Line: In a perspective drawing, the plane where objects appear to rest.
Hardening: The process by which a piece of metal is hardened by heating it to or above the critical temperature then cooling it rapidly, usually by quenching in an oil or water solution.
Hard Drive: A magnetic storage device used in computer systems.
Hardness: The measure of a material's resistance to deformation by surface indentation or by abrasion.
Heat Capacity: thermal capacity, ratio of the change in heat energy of a unit mass of a substance to the change in temperature of the substance
Heat Engine: Device that converts the energy of heat into mechanical energy
Histogram: A bar graph that shows the frequency of events occurring for a given range.
Hopper: A storage or supply bin that is used in a manufacturing system.
Horizon Line: In a perspective drawing, the imaginary line at eye level used as a construction line.
Horizontal: A line parallel to the horizon.
Hot forming: The process of working metal into shape while either in a molten or plastic state.
Hydraulic fluid: A liquid that is used in hydraulic systems to transfer energy; usually an oil-based substance
Hypothesis: An educated guess on the predicted outcomes of a series of events
Hysteresis: Literally translated -Lagging behind- When a magnetic field is created the flux lags the increase or decrease of magnetizing force. Hysteresis results from the fact that the magnetic dipoles are not perfectly aligned. With rapidly reversing alternating current the Hysteresis can cause a considerable loss of energy overcoming the internal friction of the molecular dipoles.
Impending Motion: Motion that is on the verge of occurring, but not yet present.
Impact Testing: Testing used to determine a material’s ability to withstand impact loads without fracturing.
Inclined plane: A flat sloping surface along which an object can be pushed or pulled; a plane surface that makes an oblique angle with the plane of the horizon.  One of six simple machines.
Inclusion: A foreign or impurity phase in a solid.
Induction hardening: A process of hardening a ferrous alloy by heating it above the transformation range by means of electrical induction, and then cooling as required.
Industrial Age: Age characterized by the advent of manufacturing machinery and the movement of populations to cities from farms
Infiltration: (Thermal definition) A mechanism of heat transfer in which cold (or hot) outside air infiltrates a heated (or cooled) building, displacing heated (or cooled) air. This requires additional energy be expended to heat (cool) the newly infiltrated air.
Information Age: Age characterized by the rise of Internet communications
Initial Velocity: The velocity of an object at the beginning of the object’s motion
Innovation: the introduction of something new; a new idea, method, or device.
Injection molding: The process of forcing a heated soft plastic into a mold cavity where it is cooled and hardens.
Interactive: Mutual or reciprocal communication between people and/or systems.
Interpersonal Skills: Those skills which enable an individual to work with others in a pleasant and productive manner.
Interface: The interconnection between components or systems.
I/O: Input Output
Iron Age: The period of human culture characterized by the smelting of iron and its use in industry beginning somewhat before 1000 B.C. in western Asia and Egypt.
Isometric: A drawing projected so that the plane of projection of a three-dimensional drawing forms equal angles (120 degrees) to each of the three axes of the object.
Job Function: Actual duties performed regardless of title.
K-value: A numeric expression of a material’s ability to conduct heat energy on a unit-thickness basis.
Key: A part used to transfer torque between a shaft and a hub
Key Seat: A groove or channel cut in a shaft for the key to fit in
Kilo: a prefix meaning a thousand or 1000 or 103; symbol: k
Kinetic Energy: The energy of an object due to its mass and motion; calculated using the objects mass, m, and velocity, v. 
Knurling: The process of impressing a diamond or straight line pattern on a material for the purpose of improving the appearance or providing a gripping surface.
Laser: Light Amplification by the Stimulated Emission of Radiation. A device that produces a concentrated beam of light
Law of Gravitation: Governs the mutual attraction between bodies.
Where:
F=the mutual force of attraction between the two particles
G=a universal constant called the constant of gravitation
M1M2= the masses of the two particles multiplied together
r=the distance between the centers of the particles
 LCL: Lower Control Limit (see definition for control limits)
LSL: Lower Specification Limit (see definition for specification limits)
Lathe: A machine tool in which the work material is rotated around a fixed horizontal axis and cut by a tool that is mounted on a movable carriage.
Lever: A rigid piece that transmits and modifies force or motion when forces are applied at two points and it turns about a third; specifically: a rigid bar used to exert a pressure or sustain a weight at one point of its length by the application of a force at a second and turning at a third on a fulcrum.
Liability: Having a legal responsibility for the failure of a product
Line: The path of an infinite series of points. A line has length, but not width or thickness.
Line Graph: A diagram, or a visual representation, using a broken line to show the relationship between certain sets of numbers.
Line Segment: A portion of a line that is defined by two points.
Line Weight: The width and darkness of a line.
Linkage: A mechanical system of related moving parts or connections.
Load: A force applied to an object (e.g. “a 30 lb load”)
Lobe: The highest point of a cam surface
Longitudinal axis: In the Cartesian coordinate system, this would be the “ X “ axis. Machine tools are generally designed for three axes of motion (X, Y, Z) and an axis of rotation.
Lot: A group of products shipped or received which is supposed to have a uniform level of quality throughout.
Lubrication: Providing a substance such as grease to reduce friction between moving objects.
Magnetic: Of or relating to a magnet or to magnetism; a magnetic material is attracted to magnets.
Magnetism: A force that exists around magnets that attracts ferrous materials and is used in motors and generators.
Malleability: The property of a material which enables it to undergo considerable plastic deformation under compression before fracture.
Manual: An act or process done by humans.
Manual machining: Describes the operation of a machine tool by a human operator. No computer control is involved.
Manufacturing: The total process of design, application, and production.
Martensite: A distinctive needle like structure existing in steel as a transition stage in the transformation of austenite. It is the hardest constituent of steel of eutectoid composition. It is produced by rapid cooling from quenching temperature and is the chief constituent of hardened carbon tool steels. Martensite is magnetic.
Mass: The quantity of matter, which a material contains.
Mass properties: Descriptive characteristics of an object in a 3D model.
Matrix: A chart for systematic search of possible combinations, considering several systems’ variables at once.
Max: The largest number in a data set.
Maximum Height: In the parabolic curve a projectile travels the greatest elevation the particle obtains occurs at the horizontal coordinate of the Range/2.
Mean: The arithmetic average of a sample of measurements.
Mean Time Between Failure (MTBF): The average time of operation before a device is likely to fail. This is a statistical value based on testing of representative samples of some product.
Mechanical: A form of energy, which uses motion to do work.
Mechanical Energy: The energy, which is possessed by an object due to its motion or its stored energy of position.
Mechanical fastener: A mechanical device such as a nail, screw, bolt, and etc. that is used to fasten two parts together.
Median: The middle value in a rank order data sample. Half the values will be greater and half the values will be less than the median.
Melting point: Temperature at which a material changes between solid and liquid states.
Memory: Ability of a circuit’s output to remain at one state even after the input condition that caused that state is removed.
Metal: An opaque lustrous elemental chemical substance that is a good conductor of heat and electricity and, when polished, a good reflector of light; most elemental metals are malleable, ductile, and are generally denser than the other elemental substances; metals are structurally distinguished from nonmetals by their atomic bonding and electron availability; the electron band structure of metals is characterized by a partially filled valence band; the "free electrons" lost from the outer shells of metallic atoms are available to carry an electric current; the defining property of a metal is that it is an element with a positive thermal coefficient of resistively, meaning the electrical resistively of a metal continuously increases as temperature increases.
Metric system: A measuring system in which the fundamental units are the meter, kilogram and second.
Micro: a prefix meaning a millionth or 1/1000000 or 10-6; symbol: m, “mu”
Micrometer: A precision measuring instrument, which uses a precision screw and a graduated scale.
Microprocessor: A complex digital chip that performs the computer functions of arithmetic, logic, and supervision.
Milli: a prefix meaning a thousandth or 1/1000 or 103; symbol: m
Milling: A process of cutting or material removal, which combines a rotating cutter and a traversing worktable allowing for processes such as slotting, facing and pocketing.
Min: The smallest value in a data set
Mock-up: A full-sized structural model built accurately to scale chiefly for study, testing, or display.
Mode: The number that occurs most often in a data set.
Modeling: Representation of a problem or system.
Modeling Process: The process of creating a solid, mathematical, or other representation for the purpose of conducting a test.
Modulus of Elasticity: The slope of the line in the linear elastic region created by the stress on the object divided by the strain
Moment: The tendency to rotate about a point determined by the product of a force multiplied by the distance from this force to this point
Moment of inertia: An indication of the stiffness of a particular shape. The higher the moment of inertia, the less the deflection.
Motor: A device used to convert electrical energy to mechanical energy.
 Necking: Reduction of the cross-sectional area of a material in a localized area caused by uniaxial tension.
Newton’s First Law: (The Law of Inertia) – Objects at rest tend to stay at rest, and objects in motion tend to stay in motion at a constant speed in a straight line unless acted upon by an unbalanced force.
Newton’s Second Law: The net force acting on an object in a given direction is equal to the mass of the object multiplied by the acceleration of the object in the same direction as the net force.
Newton’s Third Law: The force of one object (object 1) acting on another object (object 2) is equal in magnitude and opposite in direction to the force of the second object acting upon the first.
Nitride: A compound of nitrogen and a metal.
Non-Destructive Testing: Material or product testing in which information is learned about the material/product via careful measurements and recordings without destroying the material/product.
Normal distribution: A statistical curve that is bell shaped and shows the frequency distribution for measured data. 68% of data will be ± 1 standard deviation from the mean, 95.5% of data will be ± 2 standard deviation from the mean, and 99.7% will be ± 3 standard deviation from the mean.
Normal Stress: Stress perpendicular to the area within the material that is resisting the stress.
Nominal Group Technique: Utilizes a single, trained leader to coordinate individual input ideas.
Non-Traditional: Unique, creative, outside the norm.
Normalizing: A heat treatment applied to steel. Involves heating above the critical range followed by cooling in still air. Is performed to refine the crystal structure and eliminate internal stress.
Nuclear energy: Nuclear energy is the energy associated with nuclear bonding of the nucleus of an atom. (Nuclear energy is the energy, E, represented in the famous equation E=mc2. The mass in this equation is not the mass of the nucleus. The mass of an atom’s nucleus is actually less than the sum of the mass of the individual protons and neutrons within the nucleus. The difference between these masses is known as the “mass defect,” and is the “m” in the E=mc2. In addition, “c” is the speed of light.)
Object: Something visible or tangible.
Object Line: Slightly lighter than a profile line, used to add all details to a sketch.
Oblique: A form of pictorial sketch in which two axes are at right angles to each other (one vertical, one horizontal) and the depth axis is at an oblique angle.
Offset method: A way of determining the yield point on a stress-strain curve when it is not visibly identifiable.
Ohm’s Law: The relationship of voltage, current and resistance in a circuit I=V/R, V=IR, R=V/I
Open loop: A control system where there is no feedback circuitry.
Optical: Of or relating to the science of optics or vision.
Optimization: Process of making a system or design as functional or effective as possible.
Order of Views: The relationship between the views in orthographic projection.
Organic: Designation of any chemical compound containing carbon with the exception of some of the simple compounds of carbon, such as carbon dioxide, which are frequently classified as inorganic.
Orthographic: Right angle projection. The views of an object are drawn in perpendicular planes to one another.
Outside Suppliers: Vendors who provide products or services to a company.
Out-sourcing: The process where by a company buys certain products, subassemblies, or services from outside vendors.
Oxide: Compound of oxygen with another element.
Parallel: Multiple pathways in a circuit.
Particle: A body of negligible dimensions or when the dimensions of a body are irrelevant to the description of its motion. E.g. an airplane wing vs. the flight from NY to LA.
Pascal’s Law: A law that states when a force is exerted on a fluid, the fluid transfers this force equally against the walls of the vessel.
Pattern: A regular or repeated design, form, order, or arrangement. Duplicates one or more components and arranges the resulting occurrences in a circular or rectangular pattern.
Pearlite: Lamellar structure resembling mother of pearl. A compound of iron and carbon occurring in steel as a result of the transformation of austenite into aggregations of ferrite and iron carbide.
Performance: The manner in which a mechanism or part behaves.
Period: (Re: cam) the time it takes for one complete cycle of the follower motion.
Phase: A volume of material that contains no discontinuity in either composition or crystal structure.
Photo-resistor: A device that changes resistance according to light intensity.
Phototransistor: A semiconductor switch that produces an output when light falls on it.
Physical: Having material existence: perceptible especially through the senses and subject to the laws of nature.
Pictograph: Where symbols represent data on a graph.
Picture Plane: In a perspective drawing, it is the plane of projection.
Pie Chart: A chart that represents data in the form of slices from a 3-D circle.
Pitch: A distance of uniform measure determined at a point on one unit to the same corresponding point on the next unit; used in threads , springs, and other machine parts.
Plastics: Any of numerous organic synthetic or processed materials that are mostly thermoplastic or thermosetting polymers of high molecular weight and that can be made into objects.
Polymer: A high-molecular-weight organic compound, natural or synthetic, whose structure can be represented by a repeated small unit (mer). These long molecular chains consist of repeating chemical units held together by covalent bonds formed by a polymerization reaction. 
Porosity: The quality or state of being porous; the ratio of the volume of interstices of a material to the volume of its mass.
Position control: A system that uses the location of objects to control functions.
Posture: The position or bearing of the body whether characteristic or assumed for a special purpose.
Potential Energy: Stored energy; (Gravitational potential energy is stored energy due to elevated position of an object: PE = mgh; Elastic potential energy is stored energy in elastic materials: PE = ½ kx2).
Potentiometer: A variable resistor.
Power: Force over time. Measured in Ft Lbs  Newton Meters or Watts.
Pressure: The force generated when energy is applied to a fluid; force per unit area.
Problem solving method: Systematic efforts associated with large-scale problems, projects, or designs.
Process control: To monitor and control a process so that the quality of the output/product improves.
Process: The action of going through several steps to reach a desired goal.
Processor: An electronic device that operates on data.
Product: The end result of a manufacturing process or processes.
Probability:The system of mathematics that assigns odds or the chances of an event occurring given certain parameters.
Production: The act of manufacturing a part or product.
Profile Line: In sketching, a dark heavy line that outlines the object drawn.
Projection Plane:  An imaginary plane in the line of sight on which an image appears.
Proportion:  Proportion is a Principle of Design. Comparative relationship between things with respect to size.
Programmable Logic Controller (PLC): A microprocessor used for control engineering, primarily to replace relay logic controllers.
Programming language: A set of instructions used to operate a machine or processor to perform a task.
Projectile Motion: The motion of objects launched in space with negligible air resistance.
Public Welfare: Common good of society
Pulley: A wheel-like simple machine used to reduce input force, change the direction of force applied, or to increase the input distance. 
Pump: A device that converts mechanical energy to fluid energy.
Qualitative: Of, relating to, or involving the measurement of quality or kind without extensive mathematical analysis
Quality assurance: The use of quality control techniques associated with a process.
Quality control: The prevention of bad parts by the use of statistical techniques
Quality: The degree of customer satisfaction of a product with respect to its use.
Quantitative: Relating to, or expressible in terms of quantity, typically displayed in a line graph.
Quenching: In the heat-treating of metals, the step of cooling metals rapidly in order to obtain desired properties; most commonly accomplished by immersing the metal in oil or water. In the case of most copper base alloys, quenching has no effect other than to hasten cooling.
Range: Indicates amount of variation that exists in the machine process.

R-Value: A numeric expression of thermal insulation. R-values are the reciprocals of U-values.

Racial Bias: A settled or prejudicial outlook toward various races.

Radiation: (Thermal definition) Transfer of heat by temporarily transforming the heat (kinetic motion of an objects atoms or molecules) into electromagnetic waves (in the infrared part of the EM spectrum). These waves then travel until absorbed by another object and transferred back into atomic/molecular kinetic energy, which is heat. 

Ram: Random Access Memory.

Range: a) The horizontal distance traveled by a projectile. b) The difference between the largest and smallest piece of numerical data.

Ratchet:  a mechanism that consists of a bar or wheel having inclined teeth into which a pawl drops so that motion can be imparted to the wheel or bar, governed, or prevented and that is used in a hand tool (as a wrench or screwdriver) to allow effective motion in one direction only.

Reaction: Reactions are passive forces that are induced at the supports of a structure.

Receiver: A device that accepts signals from the emitter and is used in control systems.

Reciprocating: Motion back and forth along a linear path.
Rectification: The process of converting AC into DC.
Redundant: An additional part or subsystem that is added to a system to increase the overall system reliability. Redundant components serve their function in parallel; as long as any one redundant component is functional, the entire system still functions as designed.
Relay: Electromechanical switch where contacts are opened or closed by a control circuit in order to switch a secondary circuit.
Reliability: The probability of satisfactory operation of the product in a given environment over a specified time interval.
Research: Careful or diligent search; studious inquiry or examination; especially : investigation or experimentation aimed at the discovery and interpretation of facts, revision of accepted theories or laws in the light of new facts, or practical application of such new or revised theories or laws; the collecting of information about a particular subject.
Resilience: The tendency of a material to return to its original shape after the removal of a stress that has produced elastic strain.
Resistance: The ratio of the potential difference across an electrical component to the current passing through it. It is thus a measure of the component's opposition to the flow of electric charge. In general, the resistance of a metallic conductor increases with temperature whereas the resistance of a semiconductor decreases with temperature.
Resistor: A component used for introducing resistance into a circuit.
Resume: A document which briefly summarizes who you are; it contains your education, work experience, accomplishments, and other necessary personal information.
Rise: The segment of cam rotation that causes the follower to move upward.
Rivet: Mechanical fastener with a large head used for joining two parts together through a hole. The rivet is clinched by forming a second head on the opposite side.
Robotics: The specialized field of engineering and computer science that deals with the design and application of robots.
Role Model: A person whose behavior in a particular role is imitated by others.
Rolling: A process in which a heated or cold material is passed between rollers, squeezing it into various shapes and thickness. Some applications include rods, bars, sheet, plates, and foils.
ROM: Read Only Memory.
Rotation: Clockwise or counterclockwise spin of an object about its own axis.
Rupture Strength: The stress at which a material ruptures.
Sample: A portion of the product randomly taken for testing so decisions can be made about the whole.
Scale: A graduated series of numbers used for measurement purposes.
Scale: The ability to change the proportions or size of one part of the image in relationship to the other.
Scalar Quantity: A quantity that can be described by magnitude only; answers the question “how much?” Examples: mass, time.
Screw: A simple machine that uses threads to apply force; a spiral inclined plane surrounding a center shaft.
Seals: A device to prevent the passage or return of gas, liquid or air into a pipe or container, a tight and perfect closure.
Semiconductor: Materials whose electrical conductivity can be precisely altered by appropriate manufacturing processes.
Separating: The process by which a material is divided into two or more parts.
Series: A circuit with only one pathway for electrons.
Shafts: Cylindrical rods that support pulleys, gears, and sprockets to transmit torque. 
Shape: The physical geometry of a model.
Shear: Force that acts parallel to the surface of the material.
Shearing: The process of separating a material by applying pressure from opposing directions; the area of separation is parallel to the force applied.
SI: (System International) see metric system.
Sigma: Greek letter that is associated with the standard deviation in statistics and stress in strengths of materials; s
Simple Machine: Any one of the mechanisms which were once considered to be the basic elements from which all machines were composed. These include the lever, the wheel and axle, the pulley, the inclined plane, the wedge, and the screw.
Sketch: A freehand drawing of an idea, or solution to a problem without concern for detail.
Slope: An incline or decline mathematically calculated as the rise divided by the run.
Soldering: The joining of metal surfaces with a different metal (solder) that melts at a temperature below the red heat temperature of iron.
Solenoid: An electromagnetic device that converts electrical energy into linear motion.
Solid modeling: Three-dimensional CAD representation used to describe, simulate, and predict the behavior of objects.
Solution: A satisfactory or possibly satisfactory answer to a problem.
Space Age: Relating to, or befitting the age of space exploration.
Spatial Configuration: The relative arrangement of parts or elements within three-dimensional space.
Specification Limits: (Lower and upper specification limits (LSL and USL)); these are the actual limits that are usually set based on customer needs.
Spinning: The procedure of making sheet metal discs into hollow shapes by pressing the metal against a rotating form (spinning chuck) by a tool.
Spline: One of a series of keyways cut around a shaft and mating hole, used to transfer power from a shaft to a hub while allowing a sliding action between the parts.
Specific Gravity: The ratio of the density of a substance to the density of some substance (as pure water) taken as a standard when both densities are obtained by weighing in air.
Spread:  The distribution of data within a statistical sample.
Spreadsheet: Software packages designed to simplify the manipulation and presentation of numbers and text; spreadsheets allow the user to change parameters of the calculation and see the effect on all calculations; also, most spreadsheets have powerful presentation software, such as graphs, bar charts, etc.
Spring  A mechanical device that stores energy by expansion or contraction due to pressure, force, or stress applied, that will release energy and return to shape when the force or stress is removed.
Sprocket: A circular mechanical device with teeth that is used to impart motion to chains.
Standard deviation: A mathematical measure of the spread in a data sample. Symbol: s, “sigma”
Standards: Benchmarks used to measure or combine results. 
Statics: The study of objects in a state of equilibrium.
Station Point: The point where the viewer stands to observe the image on the picture plane.
Statistics: 1) a branch of mathematics dealing with the collection, analysis, interpolation, and presentation of masses of numerical data; 2) a collection of quantitative data.
Statistical Process Control: SPC is a method of monitoring, controlling and, ideally, improving a process through statistical analysis. Its four basic steps include measuring the process, eliminating variances in the process to make it consistent, monitoring the process, and improving the process to its best target value.
Stereotyping: Something conforming to a fixed or general pattern.
Stone Age: The first known period of prehistoric human culture characterized by the use of stone tools.
Strain: The elongation of a material under stress divided by the material’s length prior to stress; symbol: e, “epsilon.”
Stress:  A material’s internal resistance to force; symbol: s, “sigma”; calculated by dividing the force in the material by the area of the material that is subjected to the force:
Stress-Strain Curve: A graph of stress (on the y-axis) versus strain (on the x-axis) for materials under stress; enables engineers to learn about the strength of material as it deforms elastically and plastically.
Stud: Vertical Structural member.
Surface: A two-dimensional area on a plane.
Suspension Bridge: “a bridge having a road or deck hung from a pair of steel cables, each carried by two towers, one at each bank; e.g., the Golden Gate Bridge over San Francisco Bay”
Switch: Device used to control the flow of current in a circuit.
Synchronous: An AC electric motor whose speed is dependent upon the frequency of the input current.
Synetics: A group interaction, utilizing seemingly unrelated ideas, to bring about one or two solutions.
Synthesis: The process of forming, generating or putting together ideas or parts to form a whole.
Synthetic: Not naturally occurring, manufactured.
Systematic: Marked by thoroughness and regularity, also methodical in procedure or plan
 Table: A table is made up of rows and columns of cells that you can fill with text and graphics. Tables are often used to organize and present information.
Tank: A usually large receptacle for holding, transporting, or storing liquids.
Tapping: The process of cutting an internal thread using a tap.
Technical writing: Treating a document with the goal of providing clear and concise information, rather than entertainment or story telling; a technical document/report incorporates diagrams and multi-media information to provide technical information.
Temple Stick: A temperature-sensing device that looks like a crayon and only melts when applied to the surface of a material heated to a specific, predetermined temperature.
Temperature: A measurement of how warm something is; also the average kinetic energy of the individual molecules of a substance
Tempering: A heat treating process that reduces the brittleness of a hardened piece of steel by heating it to a point below the critical temperature and cooling it at some rate.
Tension: A situation in which force is applied to an object that stretches, expands or lengthens the object.
Tensile: Of or relating to tension; a “tensile” force is a force that serves to stretch, expand, or lengthen an object.
Thermal: of, relating to, or caused by heat.
Thermal energy: Thermal energy is basically kinetic energy. It is the sum of the individual atoms’ kinetic energies. Even in a completely motionless object, the atoms from which the object is made are in constant motion and thus have thermal energy.
Thermodynamics: The study of thermal energy as it moves from one substance to another.
Thermoplastic: A material capable of being repeatedly softened by increases in temperature and hardened by decreases in temperature. Thermoplastics are those materials whose change upon heating is substantially physical rather than chemical. They are largely one- or two-dimensional molecular structures such as: nylons, polycarbonates, acetals, polysulfones, and vinyls.
Thermoset: A material, such as an epoxy or polyester resin, which has the property of undergoing a chemical reaction by the action of heat, catalyst, ultraviolet light, etc., to become a relatively insoluble and infusible substance. They develop a well-bonded three-dimensional structure upon curing. Once hardened or cross-linked, they will decompose rather than melt.
Theory: A plausible or scientifically acceptable general principle or body of principles offered to explain phenomena; (scientifically quite different from a “hunch”)
Thread: A spiral groove cut into the outside of a shaft or the inside of a hole used to hold parts together.
Threading: The process of cutting spiral mating surfaces for the purpose of providing mechanical tension between two parts. (The process of using a tap or die)
Time Line: A table listing important events for successive years within a particular historical period.
Timetable: Estimated timeline for completion of a process.
Tolerance: The difference between the maximum and minimum dimensions allowed within the design of a product.
Torque: A turning or twisting force that produces or tends to produce rotation or torsion
Torsion: The twisting or wrenching of a body by the exertion of forces tending to turn one end or part about a longitudinal axis while the other is held fast or turned in the opposite direction.
Toughness: The energy required to break a material, which is equal to the area under the stress-strain curve. The toughest materials are those with very great elongations to break accompanied by high tensile strengths such materials nearly always have yield points.
Traditional: Standard or established practice.
Transducer: A device used to inform various control systems.
Transformation: A constitutional change in a solid metal, e.g., the change from gamma to alpha iron, or the formation of pearlite from austenite.
Transverse axis: In the Cartesian coordinate system, this would be the “Z“ axis. Machine tools are generally designed for the axis of motion (X, Y, Z) and a axis of rotation.
Triple beam balance: Equipment to measure mass using gravitational pull.
Turning: Using a lathe.
U-Value: A numeric expression of a material’s thermal conductivity; the degree that heat energy can pass through a material.

UCL: Upper Control Limit (see definition for control limits)

USL: Upper Specification Limit (see definition for specification limits)
Ultimate Strength: The maximum stress a material withstands prior to necking.
Valve: Any of numerous mechanical devices by which the flow of liquid, gas, or loose material in bulk may be started, stopped, or regulated by a movable part that opens, shuts, or partially obstructs one or more ports or passageways.
Vanishing Point: The point on the horizon where parallel objects appear to intersect due to convergence.
Variation: Differences that exist in any manufacturing process. Abnormal variations need to be removed; random or normal variations cannot be removed.
Vernier caliper: Instrument to precisely measure inside and outside diameters. 
Vernier Scale: A physical scale that is used on a variety of measurement tools that allows the user to measure to one ten thousandths of an inch.
Vector Quantity: A quantity that must be described by both magnitude and direction; answers the questions “how much?” and “which way?” Examples: velocity, Force.
Velocity: The ratio of the displacement of a particle and the time interval
Vertical axis: In the Cartesian coordinate system, this would be the “Y“ axis. Machine tools are generally designed for three axes of motion (X,Y,Z) and an axis of rotation.
Vertical: Perpendicular to the horizon.
Viscosity: The thickness or flow characteristic of a liquid; the more viscous, the slower a liquid will flow.
Views: The different viewing perspectives found in mechanical drawing.
Visual Aids: Instructional devices (as a chart, map, or model) that appeals chiefly to vision use to convey difficult concepts.
Visualization: To form a mental image of something.
Vita: A document which briefly summarizes who you are; it contains your education, work experience, accomplishments, and other necessary personal information.

Voltage: The electromotive force in a circuit.
Volume: The amount of space occupied by a three-dimensional object as measured in cubic units.
Water jet: A separating process that uses a high-velocity stream of water as the cutting agent. (abrasive material is sometimes used in the water)
Watt’s Law: The mathematical relationship expressing that power is the product of Voltage and Current
Wedge: A simple machine used to change the direction of applied force via its triangular shape; used for splitting wood and rocks, raising heavy bodies, or for tightening by being driven into something.
Welding: The process of joining metal together by heating to the fusion point
Weight: The gravitational pull (force) on an object.
Wheel and Axle: a. A simple machine in which a larger diameter wheel requires less force to turn than a smaller diameter axle (e.g. valve handles, steering wheel); b. A simple machine that turns rotary motion into linear motion whereby increasing the diameter of the wheel, the linear distance traveled for one revolution of the axle can be increased; c. a rotating lever
Whistle Blowing: Public disclosure of a moral or ethical problem.
Work: Done by a force acting on an object when the point of application of that force moves through some distance and the force has a component along the line of motion
Working Circle: A circle in a displacement diagram that has a radius equal to the distance from the center of the cam to the highest point on the cam.
Working Relationship: A mutually satisfying and productive ongoing interaction.
X-bar: Average or level at which a machine or process is operating