watch vs watch glass

watch and watch glass both are nouns.

Word	Noun	Adjective	Verb	Adverb
watch	Yes	No	Yes	No
watch glass	Yes	No	No	No

watch (noun)	watch glass (noun)
a purposeful surveillance to guard or observe	a protective cover that protects the face of a watch
the rite of staying awake for devotional purposes (especially on the eve of a religious festival)	laboratory glassware; a shallow glass dish used as an evaporating surface or to cover a beaker
a small portable timepiece
a person employed to keep watch for some anticipated event
a period of time (4 or 2 hours) during which some of a ship's crew are on duty
the period during which someone (especially a guard) is on duty

watch (verb)	watch glass (verb)
find out, learn, or determine with certainty, usually by making an inquiry or other effort
look attentively
be vigilant, be on the lookout or be careful
observe without intervening
observe or determine by looking
see or watch
follow with the eyes or the mind