white mountain ash vs eucalypt

white mountain ash and eucalypt both are nouns.

Word	Noun	Adjective	Verb	Adverb
white mountain ash	Yes	No	No	No
eucalypt	Yes	No	No	No

As nouns, eucalypt is a hypernym of white mountain ash; that is, eucalypt is a word with a broader meaning than white mountain ash:

white mountain ash: large tree with dark compact bark on lower trunk but smooth and white above; yields lumber similar to that of European or American ashes
eucalypt: a tree of the genus Eucalyptus

Other hypernyms of white mountain ash include eucalyptus, eucalyptus tree.

white mountain ash (noun)	eucalypt (noun)
large tree with dark compact bark on lower trunk but smooth and white above; yields lumber similar to that of European or American ashes	a tree of the genus Eucalyptus