variance

Short definition from Wiktionary

Noun

1. 1
   The act of varying or the state of being variable.
2. 2
   A difference between what is expected and what is observed; deviation.
3. 3
   The state of differing or being in conflict.
4. 4
   An official permit to do something that is ordinarily forbidden by regulations.
5. 5
   A discrepancy between two legal documents.
6. 6
   A departure from a cause of action originally in a complaint.
7. 7
   The second central moment in probability.
8. 8
   The number of degrees of freedom in a system.
9. 9
   Covariance and contravariance generally.