American elm vs white elm

American elm and white elm both are nouns.

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

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

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

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

American elm (noun)	white 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