clepsydra vs water glass

clepsydra and water glass both are nouns.

Word	Noun	Adjective	Verb	Adverb
clepsydra	Yes	No	No	No
water glass	Yes	No	No	No

As nouns, clepsydra and water glass are synonyms defined as:

clepsydra and water glass: clock that measures time by the escape of water

Other synonyms of clepsydra include water clock.

clepsydra (noun)	water glass (noun)
clock that measures time by the escape of water	a glass for drinking water
	gauge for indicating the level of water in e.g. a tank or boiler or reservoir
	clock that measures time by the escape of water
	a viscous glass consisting of sodium silicate in solution; used as a cement or as a protective coating and to preserve eggs