The discrepancy between the result of the measurement and the true value of the quantity measured. NOTE 1: In general, 'true value' may be replaced by 'conventional true value'. NOTE 2: The discrepancy can be expressed as either: the algebraic difference between these two values, i.e. (error of measurement) = (result of measurement)  (true value), or as the quotient of that difference and the value of the quantity measured. These two forms of expression are often identified as 'absolute error' and 'relative error' respectively.
Related Terms 
ADJUSTABLE DIFFERENTIAL
A means of changing the difference between the control cutin and cutout points.

DISPOSABLE
An element intended to be discarded and replaced after one service cycle.

ABSOLUTE TEMPERATURE SCALE
A scale of temperature measurement in which zero degrees is absolute zero.

HIGH WATER INEQUALITY
The difference between the heights of the two high waters during a tidal day

GRID MAGNETIC ANGLE
Angular difference in direction between grid north and magnetic north. It is measured east or west from grid north. Grid magnetic angle is sometimes called GRID VARIATION or GRIVATION.

HELIOCENTRIC PARALLAX
The difference in the apparent direction or positions of a celestial body outside the solar system, as observed from the earth and sun. Also called STELLAR PARALLAX, ANNUAL PARALLAX

DIFFERENTIAL PRESSURE INDICATOR
An indicator which signals the difference in pressure between any two points of a system or a component.

SHEAR RATE
The difference between the velocities along the parallel faces of a fluid element divided by the distance between the faces.

DIFFERENTIAL PRESSURE INDICATOR
An indicator which signals the difference in pressure between two points, typically between the upstream and downstream sides of a filter element.

COALESCOR
A separator that divides a mixture or emulsion of two immiscible liquids using the interfacial tension between the two liquids and the difference in wetting of the two liquids on a particular porous medium.
