red elm vs slippery elm

red elm and slippery elm both are nouns.

Word	Noun	Adjective	Verb	Adverb
red elm	Yes	No	No	No
slippery elm	Yes	No	No	No

As nouns, red elm and slippery elm are synonyms defined as:

red elm and slippery elm: North American elm having rough leaves that are red when opening; yields a hard wood

Other synonyms of red elm include Ulmus rubra.

red elm (noun)	slippery elm (noun)
North American elm having rough leaves that are red when opening; yields a hard wood	North American elm having rough leaves that are red when opening; yields a hard wood
autumn-flowering elm of southeastern United States