(1) The difference between a computed, observed, or measured value or condition and the true, specified, or theoretically correct value or condition. For example, a difference of 30 metres between a computed result and the correct result.~(2) An incorrect step, process, or data definition. For example, an incorrect instruction in a computer program.~(3) An incorrect result. For example, a computed result of 12 when the correct result is 10.~(4) A human action that produces an incorrect result. For example, an incorrect action on the part of a programmer or operator. Note: While all four definitions are commonly used, one distinction assigns definition 1to the word "error," definition 2 to the word "fault," definition 3 to the word "failure," and definition 4 to the word "mistake."