holm tree vs oak

holm tree and oak both are nouns.

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

As nouns, oak is a hypernym of holm tree; that is, oak 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: a deciduous tree of the genus Quercus; has acorns and lobed leaves

Other hypernyms of holm tree include oak tree.

holm tree (noun)	oak (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
	the hard durable wood of any oak; used especially for furniture and flooring