Say what? - Hat-trick

In sports, a hat-trick (more often rendered in North America as hat trick, without the hyphen) is associated with achieving something in a group of three.

It is generally agreed that the term was originally used in cricket, and was connected with the custom of giving a hat or cap to a bowler who achieved the feat of taking three wickets in a row. It may be connected with the concept of giving someone their "cap", i.e. acknowledging them as a regular member of a representative team.

Via WordIQ