outlier

noun

1. A person or thing situated away from the main body or outside its proper place.

2. An exception.

3. geologyA part of a formation separated from the rest of the formation by erosion.

4. statisticsA value in a statistical sample which does not fit a pattern that describes most other data points; specifically, a value that lies 1.5 IQR beyond the upper or lower quartile.

5. An extreme deviation from the mean