wing elm vs elm tree

wing elm and elm tree both are nouns.

Word	Noun	Adjective	Verb	Adverb
wing elm	Yes	No	No	No
elm tree	Yes	No	No	No

As nouns, elm tree is a hypernym of wing elm; that is, elm tree is a word with a broader meaning than wing elm:

wing elm: North American elm having twigs and young branches with prominent corky projections
elm tree: any of various trees of the genus Ulmus: important timber or shade trees

Other hypernyms of wing elm include elm.

wing elm (noun)	elm tree (noun)
North American elm having twigs and young branches with prominent corky projections	any of various trees of the genus Ulmus: important timber or shade trees