Ulmus thomasii vs elm

Ulmus thomasii and elm both are nouns.

Word	Noun	Adjective	Verb	Adverb
Ulmus thomasii	Yes	No	No	No
elm	Yes	No	No	No

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

Ulmus thomasii: tall widely distributed elm of eastern North America
elm: any of various trees of the genus Ulmus: important timber or shade trees

Other hypernyms of Ulmus thomasii include elm tree.

Ulmus thomasii (noun)	elm (noun)
tall widely distributed elm of eastern North America	any of various trees of the genus Ulmus: important timber or shade trees
	hard tough wood of an elm tree; used for e.g. implements and furniture