Absolute Error

The difference between true length and measured length is called the error of measurement or absolute error.
The difference between the measured or inferred value of a quantity x0 and its actual value x, given by
delta x = x0 - x
(sometimes with the absolute value taken) is called the absolute error.

The absolute error of the sum or difference of a number of quantities is less than or equal to the sum of their absolute errors.

Sources:

English dictionary: WolframAlpha. Computational intelligence https://www.wolframalpha.com/