Noun

1. An event that departs from expectations
2. Discord that splits a group
3. The second moment around the mean; the expected value of the square of the deviations of a random variable from its mean value
4. A difference between conflicting facts or claims or opinions
5. The quality of being subject to variation
6. An official dispensation to act contrary to a rule or regulation (typically a building regulation)
7. An activity that varies from a norm or standard