mid-14c., "fact of undergoing change," from Old French variance, from Latin variantia, from variare "to change" (see vary). Meaning "state of disagreement" is recorded from early 15c. The U.S. zoning sense of "official dispensation from a building regulation" is recorded from 1925.
variance var·i·ance (vâr'ē-əns, vār'-)
n.
The state or quality of being variant or variable; a variation.
The state or fact of differing or of being in conflict.
The square of the standard deviation.
in statistics, the square of the standard deviation of a sample or set of data, used procedurally to analyze the factors that may influence the distribution or spread of the data under consideration. See mean.