Survey. 1. 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.
2. the ratio of this linear error to the perimeter of the traverse.
3. (for angles) the amount by which the sum of the observed angles fails to equal the true sum.
4. (in leveling) the amount by which an elevation determined by a series of levels fails to agree with an established elevation. Also called closing error.