the amount by which a closed traverse fails to satisfy the requirements of a true mathematical figure, as the length of line joining the true and computed position of the same point.

the ratio of this linear error to the perimeter of the traverse.

(for angles) the amount by which the sum of the observed angles fails to equal the true sum.

(in leveling) the amount by which an elevation determined by a series of levels fails to agree with an established elevation.

British Dictionary definitions for error of closure

error of closure

noun

surveyingthe amount by which a computed, plotted, or observed quantity or position differs from the true or established one, esp when plotting a closed traverseAlso called: closing error