outlier

A value that is much smaller or much larger than most of the other values in a data distribution.

There may be a good reason for this, but it may also be an error in recording results and we may choose to disregard it.

For example, here are the waiting times (in minutes) for a bus on a particular day:

12, 13, 8, 11, 15, 93, 10

The outlier is 93.