Working time outside of one's regular hours.
Workers are usually paid extra for working overtime.
The rate of pay, usually higher, for work done outside of or in addition to regular hours.
An extra period of play when a contest has a tie score at the end of regulation. (British: extra time.)
That last-second shot ties the game 99-99 and sends it to overtime!
To measure something incorrectly, as taking more time than it actually did.
Exceeding regular working hours.
Beyond the normal or usual extent.