clock 1 
(klŏk)
(klŏk)n.
1. An instrument other than a watch for measuring or indicating time, especially a mechanical or electronic device having a numbered dial and moving hands or a digital display.
2. A time clock.
3. A source of regularly occurring pulses used to measure the passage of time, as in a computer.
4. Any of various devices that indicate measurement, such as a speedometer or a taximeter.
5. A biological clock.
6. The downy flower head of a dandelion that has gone to seed.
v. clocked, clock·ing, clocks
v.tr.
1. To time, as with a stopwatch: clock a runner.
2. To register or record with a mechanical device: clocked the winds at 60 miles per hour.
3. Informal To strike or hit (someone) forcefully, especially in the face.
v.intr.
Phrasal Verb: 1. To record working hours with a time clock: clocks in at 8:00 and out at 4:00.
2. To be measured or registered, especially at a certain speed or rate. Often used with in: a fastball that clocks in at 95 miles per hour.
clock up Chiefly British Slang
Idioms: To accumulate; rack up: clocked up a number of wins.
around/round the clock
Throughout the entire 24 hours of the day; continuously.
clean (someone's) clock Slang
To beat or defeat decisively: "Immense linemen declared their intentions to clean the clocks of opposing players" (Russell Baker).
kill/run down/run out the clock
Sports To preserve a lead by maintaining possession of the ball or puck until playing time expires.
[Middle English clokke, from Old North French cloque, bell, or from Middle Dutch clocke, bell, clock, both from Medieval Latin clocca, of imitative origin.]
clocker n.
clock1