clock in Definition

clock¹
noun

1. A device for measuring and indicating time, usually by means of a digital display or pointers on a dial.

Thesaurus: timepiece, timer, timekeeper.
2. computing.
An electronic device that synchronizes processes within a computer system, by issuing signals at a constant rate.
3. A device that synchronizes the timing in switching circuits, transmission systems, etc.
the clock
4a. colloq
A mileometer;
the clock
4b. colloq
A speedometer.
5. A device for recording the arrival and departure times of employees.

Form: time clock (in full)
6. The downy seedhead of a dandelion.
7. slang
The face.

verb clocked, clocking

1. To measure or record (time) using such a device.
2. To record with a stopwatch the time taken by (a racer, etc) to complete a distance, etc.
3. colloq
To travel at (a speed as shown on a speedometer).
4. slang
To hit someone.
5. colloq
To achieve (an officially attested time) in a race.
Example: He clocked 9.89 seconds in the final
6. colloq
To turn back the mileometer of (a car), to display a lower figure than the actual mileage.
7. slang
To observe or notice someone.

Idiom: against the clock

With a time deadline.

Idiom: beat the clock

To finish before the set time limit or deadline.

Idiom: put back the clock (turn back the clock)

To seek to return to the conditions of an earlier period.

Idiom: round the clock

Throughout the day and night.
Thesaurus: night and day, continuously, twenty-four hours a day, continually, non-stop.

Idiom: watch the clock

To pay close attention to the time of day, especially in order not to exceed minimum working hours.

Etymology: 14c as clokke: from Dutch clocke bell or clock.

Phrasal Verb: clock in or on

To record one's time of arrival at a place of work.

Phrasal Verb: clock out or off

To record one's time of departure from a place of work.

Phrasal Verb: clock up something

To reach (a speed), cover (a distance), or achieve (a score), etc.