clock on

clock on (third-person singular simple present clocks on, present participle clocking on, simple past and past participle clocked on)

1. (literally, UK) To record one's time of arrival at work, traditionally by inserting one's card into a timestamping machine.
2. (by extension, UK) To begin work at the start of the day or start of one's shift.

• clock in
• clock off
• clock out