white elm vs water elm

white elm and water elm both are nouns.

Word	Noun	Adjective	Verb	Adverb
white elm	Yes	No	No	No
water elm	Yes	No	No	No

As nouns, white elm and water elm are synonyms defined as:

white elm and water elm: large ornamental tree with graceful gradually spreading branches common in eastern North America

Other synonyms of white elm include American elm, rock elm, Ulmus americana.

white elm (noun)	water elm (noun)
large ornamental tree with graceful gradually spreading branches common in eastern North America	large ornamental tree with graceful gradually spreading branches common in eastern North America
	Eurasian elm closely resembling the American elm; thrives in a moist environment