orange tree vs citrus tree

orange tree and citrus tree both are nouns.

Word	Noun	Adjective	Verb	Adverb
orange tree	Yes	No	No	No
citrus tree	Yes	No	No	No

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

orange tree: any citrus tree bearing oranges
citrus tree: any of numerous tropical usually thorny evergreen trees of the genus Citrus having leathery evergreen leaves and widely cultivated for their juicy edible fruits having leathery aromatic rinds

Other hypernyms of orange tree include citrus.

orange tree (noun)	citrus tree (noun)
any citrus tree bearing oranges	any of numerous tropical usually thorny evergreen trees of the genus Citrus having leathery evergreen leaves and widely cultivated for their juicy edible fruits having leathery aromatic rinds