Engineering Glossary: C

136 definitions in plain language.

136 terms beginning with C. Use the filter to narrow the list, or the letters to jump to another part of the glossary.

136 terms
Cable derating #
Reducing the allowed current of a cable because of heat, grouping or ambient temperature. Electrical power and machines
CAD #
Computer-aided design: software for making technical drawings and 3D models. Programming, data and computing
Calibration #
Comparing an instrument with a known standard and adjusting it so its readings are correct. Materials, manufacturing and measurement
Calorific value #
The heat released by burning a unit mass of fuel completely. Fluids, heat and thermodynamics
Cam #
A rotating or sliding shape that pushes a follower through a planned motion. Mechanical design and mechanics Read more: Cams and Followers
Cam follower #
The part that rides on a cam and moves as the cam shape dictates. Mechanical design and mechanics
CAN bus #
A robust serial bus with message priorities, used in vehicles and machinery. Automation, controls and robotics
Cantilever #
A beam fixed at one end and free at the other. Mechanical design and mechanics
Capacitance #
The ability of a capacitor to store charge for a given voltage, in farads. Electronics
Capacitive reactance #
The reactance of a capacitor: 1 ÷ (2 π f C), falling with frequency. Electrical power and machines
Capacitive sensor #
A proximity sensor that detects any material by the change in capacitance. Automation, controls and robotics
Capacitor #
A component that stores energy in an electric field between two plates and blocks DC. Electronics Read more: Capacitors
Capacity (battery) #
The charge a battery can deliver, in ampere-hours or watt-hours. Electrical power and machines
Capillary action #
The rise or fall of a liquid in a narrow tube due to surface tension and adhesion. Fluids, heat and thermodynamics
Carbon fiber #
Very strong, stiff, light fibers of carbon, used in a resin to make composites. Materials, manufacturing and measurement
Carbon steel #
Steel whose properties are mainly set by its carbon content, with only small amounts of other alloying elements. Materials, manufacturing and measurement Read more: Steel Grade Cross Reference
Carburizing #
Case hardening by adding carbon to the surface of low-carbon steel at high temperature. Materials, manufacturing and measurement
Carnot cycle #
The most efficient possible cycle between two temperatures; it sets the upper limit for heat engines. Fluids, heat and thermodynamics
Cartesian robot #
A robot that moves along three straight perpendicular axes. Also called a gantry robot. Automation, controls and robotics
Cascade control #
A control scheme with an inner loop that corrects quickly and an outer loop that sets its setpoint. Automation, controls and robotics
Case hardening #
Hardening only the surface of a part, leaving a tough core, by adding carbon or nitrogen. Also called surface hardening. Materials, manufacturing and measurement
Casting #
Making a part by pouring molten metal into a mold. Materials, manufacturing and measurement Read more: Casting, Forging and Powder Metallurgy
Cast iron #
An iron-carbon alloy with 2 to 4 percent carbon that is poured into molds; hard, brittle in tension and good in compression. Materials, manufacturing and measurement
Cavitation #
The formation and collapse of vapor bubbles in a liquid where the pressure falls below the vapor pressure; it damages pumps and propellers. Fluids, heat and thermodynamics
Cell #
One unit of a battery, giving a nominal voltage set by its chemistry. Electrical power and machines
CE marking #
A mark showing that a product meets European Union requirements for safety, health and environmental protection. Math, units, quality and workshop
Center of gravity #
The point where the whole weight of a body can be taken to act. Mechanical design and mechanics
Centrifugal force #
The apparent outward force felt in a rotating frame; in a fixed frame it is the reaction to the centripetal force. Mechanical design and mechanics
Centrifugal pump #
A pump that throws liquid outward with a spinning impeller; the most common type. Fluids, heat and thermodynamics
Centripetal acceleration #
The acceleration directed toward the center of a circular path, v² ÷ r. Mechanical design and mechanics
Centroid #
The geometric center of an area: the average position of all its points. Mechanical design and mechanics
Ceramic capacitor #
A small, low-cost capacitor with low inductance, common for decoupling. Electronics
Chain drive #
A drive that transmits power by a roller chain meshing with sprockets. Mechanical design and mechanics Read more: Chains and Sprockets
Chamfer #
A beveled edge cut at a corner to remove a sharp edge or ease assembly. Mechanical design and mechanics
Characteristic impedance #
The ratio of voltage to current of a wave on a transmission line, such as 50 or 100 ohms. Electronics
Chatter #
Self-excited vibration between a tool and workpiece that leaves a wavy surface and shortens tool life. Materials, manufacturing and measurement
Checksum #
A small value calculated from data, used to detect errors in transmission or storage. Programming, data and computing
Check valve #
A valve that lets fluid pass in one direction only. Fluids, heat and thermodynamics
Chiller #
A machine that cools water or another fluid for air conditioning or processes. Fluids, heat and thermodynamics
Chip load #
The thickness of material removed by each tooth of a cutter per revolution, also called feed per tooth. Materials, manufacturing and measurement
Choke #
An inductor used to block high-frequency signals while passing DC. Electronics
Choked flow #
The maximum flow of a gas through a restriction, reached when the speed at the throat is sonic. Fluids, heat and thermodynamics
Circuit breaker #
A switch that opens automatically when current exceeds its rating, and can be reset. Electrical power and machines Read more: Standard Breaker and Fuse Sizes
Circularity #
A tolerance on how far a cross-section of a round feature may deviate from a perfect circle. Materials, manufacturing and measurement
Circular mil #
A unit of wire cross-section area: the area of a circle one thousandth of an inch in diameter. Electrical power and machines
C language #
A compact, fast programming language close to the hardware, used for embedded systems and operating systems. Programming, data and computing Read more: C and C++ Essentials
Classification #
Predicting which category an item belongs to. Programming, data and computing
Clearance (electrical) #
The shortest distance through air between two conductive parts. Electrical power and machines
Clearance fit #
A fit in which the shaft is always smaller than the hole so the parts can move or be assembled by hand. Materials, manufacturing and measurement
Clock #
A repeating signal that sets the timing of a digital circuit. Electronics
Closed-loop control #
Control that measures the output and corrects the command to reduce the error. Also called feedback control. Automation, controls and robotics Read more: Control Systems
Cloud computing #
Using remote computers over the internet to store data and run programs. Programming, data and computing
Clustering #
Grouping similar items together without being told the groups in advance. Programming, data and computing
Clutch #
A device that connects and disconnects two shafts so torque can be transmitted when wanted. Mechanical design and mechanics
CMM #
Coordinate measuring machine: an instrument that measures a part by touching points on it with a probe. Materials, manufacturing and measurement
CNC #
Computer numerical control: machine tools driven by a stored program of coordinates and commands. Materials, manufacturing and measurement
Coaxial #
Sharing the same axis. Math, units, quality and workshop
Coefficient of friction #
The ratio of the friction force to the force pressing two surfaces together. Mechanical design and mechanics
Coefficient of performance #
The heat moved divided by the work put in for a refrigerator or heat pump; it can be greater than 1. Fluids, heat and thermodynamics
Coefficient of thermal expansion #
The fractional change in length per degree of temperature change, in µm/m·K. Fluids, heat and thermodynamics
Coil (ladder) #
A ladder symbol that sets a bit or output when the rung conditions are true. Automation, controls and robotics
Cold joint #
A poor solder joint that is dull and grainy because the metal did not get hot enough. Electronics
Collaborative robot #
A robot designed to work safely beside people without a fence. Also called a cobot. Automation, controls and robotics
Collet #
A sleeve that grips a tool or workpiece by closing around it. Materials, manufacturing and measurement
Color code #
Colored bands on a resistor that show its value and tolerance. Electronics Read more: Resistor Color Code Calculator
Combustion #
Rapid chemical reaction of a fuel with oxygen that releases heat. Fluids, heat and thermodynamics Read more: Combustion and Boiler Efficiency
Commissioning #
Starting up, adjusting and testing a system until it works as designed. Automation, controls and robotics
Common-mode rejection ratio #
How well a differential amplifier ignores signals that appear equally on both inputs. Electronics
Comparator #
A circuit that compares two voltages and gives a high or low output. Electronics
Compiler #
A program that translates source code into machine code before the program runs. Programming, data and computing
Compliance #
The deflection produced by a unit force; the reciprocal of stiffness. Mechanical design and mechanics
Composite #
A material made of two or more different materials, such as fibers in a resin, that gives properties neither has alone. Materials, manufacturing and measurement Read more: Composites and Fiber-Reinforced Plastics
Compressed air #
Air at higher than atmospheric pressure, used as an energy source. Fluids, heat and thermodynamics Read more: Compressed Air Consumption Calculator
Compressibility #
The fractional change in volume of a fluid for a change in pressure; gases are far more compressible than liquids. Fluids, heat and thermodynamics
Compression spring #
A helical spring that resists being shortened. Mechanical design and mechanics Read more: Compression Spring Design Calculator
Compressor #
A machine that raises the pressure of a gas by reducing its volume. Fluids, heat and thermodynamics
Concentric #
Sharing the same center. Math, units, quality and workshop
Concentricity #
A tolerance on how closely the axes of two round features coincide; replaced by position or runout in modern standards. Materials, manufacturing and measurement
Concept drift #
A change over time in the relationship that a model learned, which makes its predictions worse. Programming, data and computing
Condenser #
A heat exchanger that turns vapor back into liquid by removing heat. Fluids, heat and thermodynamics
Conduction #
Heat transfer through a solid or stationary fluid by molecular contact. Fluids, heat and thermodynamics Read more: Heat Transfer
Conductivity #
The reciprocal of resistivity: how easily a material carries current. Electrical power and machines
Conductor #
A material that carries electric current easily, such as copper. Electrical power and machines
Conduit #
A tube that protects and routes electrical wires. Electrical power and machines
Confidence interval #
A range that is expected to contain the true value with a stated probability, such as 95 percent. Math, units, quality and workshop
Confusion matrix #
A table that compares predicted with actual classes to show the kinds of errors a classifier makes. Programming, data and computing
Connector #
A device for joining wires or boards, which can be disconnected. Electronics
Conservation of energy #
Energy cannot be created or destroyed, only changed from one form to another. Math, units, quality and workshop
Conservation of momentum #
In a system with no outside force, the total momentum stays the same. Math, units, quality and workshop
Constant #
A named value that does not change while a program runs. Programming, data and computing
Contact (ladder) #
A ladder symbol that passes power when its bit is true (normally open) or false (normally closed). Automation, controls and robotics
Contactor #
An electrically operated switch for making and breaking a power circuit, such as a motor's. Electrical power and machines
Contact ratio #
The average number of tooth pairs in contact; a value above 1 means the teeth overlap smoothly. Mechanical design and mechanics
Continuity equation #
The statement that mass flow is the same at every section of a pipe: density times area times velocity is constant. Fluids, heat and thermodynamics Read more: Continuity, Bernoulli and the Energy Equation
Continuous beam #
A beam that rests on more than two supports. Mechanical design and mechanics
Control panel #
An enclosure that holds the controls, drives and wiring of a machine. Automation, controls and robotics Read more: System Integration
Convection #
Heat transfer by the movement of a fluid, either natural (from buoyancy) or forced (by a fan or pump). Fluids, heat and thermodynamics
Convergence #
The approach of a numerical process to its answer as it is repeated or refined. Math, units, quality and workshop
Coolant #
Fluid applied to a cutting tool to cool it, lubricate the cut and flush away chips. Materials, manufacturing and measurement
Cooling load #
The rate at which heat must be removed from a space to keep it at the set temperature. Fluids, heat and thermodynamics
Cooling tower #
A device that rejects heat from water to the air by evaporation. Fluids, heat and thermodynamics
Copper loss #
The I²R heating in the windings of a transformer or motor. Electrical power and machines
Core loss #
The energy lost in a transformer or motor core by hysteresis and eddy currents. Electrical power and machines
Coriolis effect #
The apparent deflection of a moving body in a rotating frame such as the Earth. Mechanical design and mechanics
Correlation #
A measure of how closely two quantities vary together; it does not prove that one causes the other. Math, units, quality and workshop
Corrosion #
The gradual destruction of a metal by chemical reaction with its environment. Materials, manufacturing and measurement Read more: Corrosion and Protection
Cosine #
In a right triangle, the ratio of the side next to an angle to the hypotenuse. Math, units, quality and workshop
Coulomb #
The SI unit of electric charge: the charge carried by one ampere in one second. Electrical power and machines
Counter #
A digital circuit that counts clock pulses. Electronics
Counter (PLC) #
A PLC instruction that counts events and acts when a preset number is reached. Automation, controls and robotics
Couple #
Two equal and opposite parallel forces that produce a turning effect without a net force. Mechanical design and mechanics
Coupling #
A device that connects two shafts to transmit torque, sometimes allowing for misalignment. Mechanical design and mechanics
Cp #
A process capability index: the tolerance width divided by six standard deviations of the process. Materials, manufacturing and measurement
Cpk #
A process capability index that also accounts for how well the process mean is centered between the limits. Materials, manufacturing and measurement
Crack propagation #
The growth of a crack under load or repeated loading. Mechanical design and mechanics
Crank #
A link that rotates fully about a fixed pivot. Mechanical design and mechanics
C-rate #
The charge or discharge current of a battery relative to its capacity; 1C empties the battery in one hour. Electrical power and machines
CRC #
Cyclic redundancy check: a checksum that detects accidental changes in data with high reliability. Programming, data and computing
Creep #
Slow permanent deformation of a material under constant load, important at high temperature. Mechanical design and mechanics
Creepage distance #
The shortest path along the surface of an insulator between two conductive parts. Electrical power and machines
Crevice corrosion #
Corrosion in a narrow gap where fluid stagnates, such as under a washer or gasket. Materials, manufacturing and measurement
Crimp #
A joint made by squeezing a metal terminal onto a wire. Electronics
Critical damping #
The amount of damping at which a system returns to rest as fast as possible without oscillating. Mechanical design and mechanics
Critical path #
The longest chain of dependent tasks in a project; any delay on it delays the finish. Math, units, quality and workshop
Critical speed #
The rotation speed at which a shaft's natural frequency is excited and it whirls violently. Mechanical design and mechanics
Cross product #
A way of multiplying two vectors to give a vector perpendicular to both; used for moments. Math, units, quality and workshop
Crosstalk #
Unwanted coupling of signals between nearby traces or wires. Electronics
Cross-validation #
Splitting data several times into training and test sets to estimate how well a model will perform. Programming, data and computing
CSV #
Comma-separated values: a plain text file format for tables. Programming, data and computing
Current #
The flow of electric charge, measured in amperes. Electrical power and machines Read more: Ohm’s Law and Power Calculator
Current gain #
The ratio of output current to input current of a transistor, written β or hFE. Electronics
Curve fitting #
Finding a mathematical curve that best matches a set of data points. Programming, data and computing Read more: Machine Learning
Cutoff frequency #
The frequency at which a filter's output has fallen to 70.7 percent (−3 dB) of its passband value. Electronics
Cutting speed #
The speed of the cutting edge past the workpiece, in m/min or surface feet per minute. Materials, manufacturing and measurement Read more: Speeds and Feeds
Cybersecurity (industrial) #
Protecting control systems and networks from unauthorized access and attack. Automation, controls and robotics Read more: Industrial Communication
Cylindricity #
A tolerance that limits the form of a whole cylinder: round, straight and uniform in diameter. Materials, manufacturing and measurement

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