Formerly the Instrument Society of America, now referred to as the International Society for Measurement & Control.

Temperature at which thermal energy is at a minimum. Defined as 0 Kelvin or 0 Rankine (-273.15 °C or -459.67°F).

The fraction of incident radiation absorbed by a surface, a.

Closeness of a reading or indication of a measurement device to the actual value of the quantity being measured.

The design of an instrument such that changes in ambient temperature do not affect the readings of the instrument.

The average or mean temperature of the surrounding air which comes in contact with the equipment and instruments under test.

A unit used to define the rate of flow of electricity (current) in an electrical circuit; units are one coulomb (6.25x1018 electrons) per second. Symbolized by A.

The United States standards body responsible for designating standards developed by other organizations as national standards.

A theoretical object that radiates the maximum amount of energy at a given temperature, and absorbs all the energy incident upon it. A blackbody is not necessarily black. (The name blackbody was chose [..]

The temperature at which a substance in the liquid phase transforms to the gaseous phase. Commonly refers to the boiling point of water, 100°C (212°F).