Watch
Watch (timepiece)
A small clock worn on the wrist.
Arjun checked his watch before the exam ended.
Watch (to look)
To look at something carefully for some time.
We watched the kite festival from the terrace.
Watch (guard duty)
A time of guarding or keeping a lookout.
The fishermen kept watch through the night for the storm.
Remember: All three are about keeping an eye on things: you watch, you keep watch, and a watch keeps an eye on the time.