var·i·ance 
(vârē-əns, văr-)
(vârē-əns, văr-)n.
1. The state or quality of being variant or variable; variation: considerable variance in temperature across the region.
2.
a. Difference or inconsistency: Your behavior is at variance with your beliefs.
b. The state or fact of being in disagreement or in conflict: I am at variance with her over who should pay for the damage.
3. Law
a. A discrepancy between two statements or documents, especially between the charge in a criminal indictment and the evidence presented.
b. An exception to the application of a usual rule, granted by an authority on the basis of hardship or practicality: a zoning variance.
4. Statistics The square of the standard deviation.
5. Chemistry The number of thermodynamic variables, such as temperature and pressure, required to specify a state of equilibrium of a system, given by the phase rule; the degrees of freedom of a system.