1 general:: Phrase(s): clock in to record one’s time of arrival, usually by punching a time clock. • What time did she clock in? • She forgot to clock in today., Phrase(s): clock someone in to observe and record someone’s time of arrival. • The manager says he clocked you in at noon. That’s a bit late, isn’t it?
McGrawhill's American Idioms And Phrasal Verbs
2 general:: Begin work, as in She clocked in late again.
American Heritage Idioms