variance V, σ 2

The sum of the squares of the standard deviations, expressing the contributions to the overall precision from various sources of uncertainty.
Orange Book, p. 5
PAC, 1994, 66, 595 (Nomenclature for the presentation of results of chemical analysis (IUPAC Recommendations 1994)) on page 601
PAC, 1990, 62, 2167 (Glossary of atmospheric chemistry terms (Recommendations 1990)) on page 2218