kingbird vs tyrant bird

kingbird and tyrant bird both are nouns.

Word	Noun	Adjective	Verb	Adverb
kingbird	Yes	No	No	No
tyrant bird	Yes	No	No	No

As nouns, tyrant bird is a hypernym of kingbird; that is, tyrant bird is a word with a broader meaning than kingbird:

kingbird: large American flycatcher
tyrant bird: large American birds that characteristically catch insects on the wing

Other hypernyms of kingbird include flycatcher, New World flycatcher, tyrant flycatcher.

kingbird (noun)	tyrant bird (noun)
large American flycatcher	large American birds that characteristically catch insects on the wing