holm tree vs oak tree

holm tree and oak tree both are nouns.

Word	Noun	Adjective	Verb	Adverb
holm tree	Yes	No	No	No
oak tree	Yes	No	No	No

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

holm tree: evergreen oak of southern Europe having leaves somewhat resembling those of holly; yields a hard wood
oak tree: a deciduous tree of the genus Quercus; has acorns and lobed leaves

Other hypernyms of holm tree include oak.

holm tree (noun)	oak tree (noun)
evergreen oak of southern Europe having leaves somewhat resembling those of holly; yields a hard wood	a deciduous tree of the genus Quercus; has acorns and lobed leaves