Engineering Glossary: A
54 definitions in plain language.
54 terms beginning with A. Use the filter to narrow the list, or the letters to jump to another part of the glossary.
54 terms
- Absolute maximum rating #
- A limit that must never be exceeded, even briefly, without risking damage to a component. Electronics
- Absolute pressure #
- Pressure measured relative to a perfect vacuum: gauge pressure plus atmospheric pressure. Fluids, heat and thermodynamics
- Absolute zero #
- The lowest possible temperature, 0 K or −273.15 C, at which a perfect gas would have no thermal energy. Fluids, heat and thermodynamics
- Acceleration #
- The rate of change of velocity, in m/s². Math, units, quality and workshop
- Accelerometer #
- A sensor that measures acceleration, used for vibration and motion. Automation, controls and robotics
- Accumulator #
- A vessel that stores hydraulic fluid under pressure, to smooth out pressure and store energy. Fluids, heat and thermodynamics
- Accuracy #
- How close a measurement is to the true value. Materials, manufacturing and measurement
- Actuator #
- A device that converts a control signal into physical motion or force. Automation, controls and robotics
- ADC #
- Analog-to-digital converter: a circuit that turns a voltage into a number. Electronics Read more: Analog Circuits and Sensing
- Addendum #
- The height of a gear tooth above the pitch circle. Mechanical design and mechanics
- Additive manufacturing #
- The formal term for 3D printing and related processes that build parts by adding material. Materials, manufacturing and measurement
- Adiabatic process #
- A process in which no heat is exchanged with the surroundings. Fluids, heat and thermodynamics
- Affinity laws #
- Rules that give how pump flow, head and power change with speed: flow with speed, head with speed squared, power with speed cubed. Fluids, heat and thermodynamics
- Air change rate #
- The number of times per hour that the volume of air in a space is replaced. Fluids, heat and thermodynamics
- Air dryer #
- A device that removes moisture from compressed air. Fluids, heat and thermodynamics
- Alarm #
- A message that warns an operator that a condition needs attention. Automation, controls and robotics
- Algorithm #
- A step-by-step procedure for solving a problem or doing a calculation. Programming, data and computing
- Aliasing #
- A false low-frequency signal that appears when a signal is sampled too slowly. Electronics
- Allowable stress #
- The largest stress a design permits, equal to the strength divided by the safety factor. Mechanical design and mechanics
- Allowance #
- The intended difference between the sizes of mating parts; the tightest fit that is wanted. Materials, manufacturing and measurement
- Alloy #
- A metal made by mixing two or more elements, at least one of them a metal, to give properties the pure metal lacks. Materials, manufacturing and measurement
- Alloy steel #
- Steel with added elements such as chromium, nickel or molybdenum to improve strength, toughness or hardenability. Materials, manufacturing and measurement
- Alternating current #
- Current that reverses direction periodically; also called AC. Electrical power and machines Read more: AC Power Basics
- Alternator #
- An AC generator, such as the one in a car. Electrical power and machines
- Aluminum alloy #
- An alloy of aluminum with elements such as magnesium, silicon, copper or zinc. Materials, manufacturing and measurement Read more: Aluminum Alloys and Tempers
- American wire gauge #
- The US system of wire sizes, in which a larger number means a thinner wire. Electrical power and machines Read more: AWG Wire Gauge Table
- Ampacity #
- The largest current a conductor can carry continuously without exceeding its temperature rating. Electrical power and machines Read more: Wire Ampacity and Voltage Drop Calculator
- Ampere #
- The SI unit of current: one coulomb of charge per second. Electrical power and machines
- Amplifier #
- A circuit that increases the power, voltage or current of a signal. Electronics
- Amplitude #
- The peak value of an alternating quantity. Electrical power and machines
- Analog I/O #
- Inputs and outputs that carry a continuously varying value, such as 4 to 20 mA. Automation, controls and robotics Read more: 4–20mA / 0–10V Analog Scaling Tool
- Angularity #
- A tolerance on how closely a surface or axis must be at a stated angle to a datum. Materials, manufacturing and measurement
- Angular momentum #
- The rotational equivalent of momentum: moment of inertia times angular velocity. Mechanical design and mechanics
- Angular velocity #
- The rate of rotation, in radians per second. Math, units, quality and workshop
- Annealing #
- Heating a metal and cooling it slowly to soften it, relieve stress and refine the structure. Materials, manufacturing and measurement Read more: Steels and Heat Treatment
- Anodizing #
- An electrochemical process that thickens the natural oxide layer on aluminum for protection and color. Materials, manufacturing and measurement
- Anomaly detection #
- Finding data that differs from the normal pattern, such as a machine starting to fail. Programming, data and computing
- ANSI #
- American National Standards Institute, which coordinates US standards. Math, units, quality and workshop
- Anti-aliasing filter #
- A low-pass filter placed before an ADC to remove frequencies above half the sampling rate. Electronics
- API #
- Application programming interface: the set of functions and rules for using a piece of software. Programming, data and computing
- Apparent power #
- The product of RMS voltage and current in an AC circuit, in volt-amperes. Electrical power and machines
- Arc flash #
- An explosive release of energy from an electric arc fault, a serious hazard to workers. Electrical power and machines
- Arduino #
- An open-source microcontroller platform with simple hardware and software for beginners and prototyping. Programming, data and computing
- Array #
- An ordered collection of values of the same type, accessed by index. Programming, data and computing
- Articulated robot #
- A robot arm with rotary joints, usually six, like a human arm. Automation, controls and robotics
- ASCII #
- A standard code that assigns numbers to letters, digits and symbols. Programming, data and computing Read more: ASCII Table
- ASME #
- American Society of Mechanical Engineers, which publishes codes and standards such as those for boilers and pressure vessels. Math, units, quality and workshop
- ASTM #
- A standards organization (formerly the American Society for Testing and Materials) that publishes material and test standards. Math, units, quality and workshop
- Atmospheric pressure #
- The pressure of the air around us, 101.325 kPa (14.7 psi) at sea level on a standard day. Fluids, heat and thermodynamics Read more: Standard Atmosphere Table (ISA)
- Austenite #
- The high-temperature form of steel (face-centered cubic iron) that can dissolve carbon; some stainless steels keep it at room temperature. Materials, manufacturing and measurement
- Austenitic stainless steel #
- A non-magnetic, tough and weldable stainless steel family with chromium and nickel, such as 304 and 316. Materials, manufacturing and measurement
- Authentication #
- Proving who a user or device is. Programming, data and computing
- Automation #
- Using machines, controls and software to carry out a process with little human effort. Automation, controls and robotics Read more: Automation
- Autotransformer #
- A transformer with a single winding that is tapped to give a different voltage. Electrical power and machines