Terminology

A pressure gauge referenced to a perfect vacuum. At local atmospheric conditions, an absolute gauge indicates atmospheric pressure rather than zero.

The closeness of an indicated value to a reference value under stated conditions. Accuracy is not the same as display resolution.

A mechanical pointer that can be repositioned for alignment or zero adjustment according to the instrument manufacturer's procedure.

Lost motion in a mechanical system that can produce a different indication when the input direction changes.

An instrument that measures atmospheric pressure, normally on an absolute-pressure basis.

A documented comparison between an instrument indication and reference values, including associated uncertainty where applicable. See Calibration.

A gradual change in indication over time while the input is believed to remain constant.

The range value used as the basis for a full-scale specification.

Pressure referenced to local atmospheric pressure. A vented gauge normally reads zero when exposed to the surrounding atmosphere.

A difference in indication at the same input depending on whether the measurement point is approached from above or below.

The closeness of repeated results to one another. Precision alone does not establish that the result is accurate.

The interval of values an instrument is designed or configured to measure.

Agreement among repeated readings obtained under specified repeat conditions.

The smallest displayed or detectable increment. A high-resolution display does not by itself guarantee high measurement accuracy.

The indication or reference condition associated with no applied measurand, as defined for the instrument.