[1] : WordNet (r) 2.0

clock on
     v : register one's arrival at work syn: clock in, punch in
         ant: clock out, clock out
see also:
clock in punch in clock out 

Clock >> C Words
Clock, definition of term: Clock
clock_pag1.html

Clock In >> C Words
Clock In, definition of term: Clock In
clock+in_pag1.html

Clock Speed >> C Words
Clock Speed, definition of term: Clock Speed
clock+speed_pag1.html

Water Clock >> W Words
Water Clock, definition of term: Water Clock
water+clock_pag1.html

Time Clock >> T Words
Time Clock, definition of term: Time Clock
time+clock_pag1.html

Sidereal Clock >> S Words
Sidereal Clock, definition of term: Sidereal Clock
sidereal+clock_pag1.html

Pendulum Clock >> P Words
Pendulum Clock, definition of term: Pendulum Clock
pendulum+clock_pag1.html

Atomic Clock >> A Words
Atomic Clock, definition of term: Atomic Clock
atomic+clock_pag1.html