Real Dictionary

time clock in American English
a clock with a mechanism for recording on a timecard the time an employee begins and ends a work period
noun: a clock with an attachment that may be manually activated to stamp or otherwise record the exact time on a card or tape, used to keep a record of the time of something, as of the arrival and departure of employees

time clock in British English
noun: a clock which records, by punching or stamping cards inserted into it, the time of arrival or departure of people, such as employees in a factory