Discrepancy between a computed, observed or measured value or condition and the true, specified or theoretically correct value or condition. NOTE 1 An error can be caused by a faulty item, e.g. a computing error made by faulty computer equipment. NOTE 2 The French term “erreur” can also designate a mistake.
Source: API STD 2000, Venting Atmospheric and Low-pressure Storage Tanks, Sixth Edition, November 2009. Global Standards