browser vs watcher

browser and watcher both are nouns.

Word	Noun	Adjective	Verb	Adverb
browser	Yes	No	No	No
watcher	Yes	No	No	No

As nouns, watcher is a hypernym of browser; that is, watcher is a word with a broader meaning than browser:

browser: a viewer who looks around casually without seeking anything in particular
watcher: a close observer; someone who looks at something (such as an exhibition of some kind)

Other hypernyms of browser include looker, spectator, viewer, witness.

browser (noun)	watcher (noun)
a program used to view HTML documents	a guard who keeps watch
a viewer who looks around casually without seeking anything in particular	a close observer; someone who looks at something (such as an exhibition of some kind)
	a person who keeps a devotional vigil by a sick bed or by a dead body