watch

\ \ [OE] Ultimately, watch and wake are the same word. The two verbs share a common ancestor (prehistoric Germanic *wakōjan), and to begin with watch was used for ‘be awake’ (‘He sleepeth on the day and watcheth all the night’, John Lydgate, 1430). The notion of being ‘alert and vigilant’, of being ‘on the look-out’, is implicit in that of being ‘awake’ (indeed, vigil and vigilant are members of the same word family), but watch did not develop fully into ‘observe, look at closely’ until the 14th century.

\ \ The sort of watch that tells the time is probably so called not because you look at it to see what the time is, but because originally it woke you up. The earliest records of the noun’s application to a timepiece (in the 15th century) refer to an ‘alarm clock’; it was not used for what we would today recognize as a ‘watch’ until the end of the 16th century.

\ \ Cf.⇒ VEGETABLE, VIGIL, VIGOUR, WAFT, WAIT, WAKE