kingbird vs flycatcher

kingbird and flycatcher both are nouns.

Word	Noun	Adjective	Verb	Adverb
kingbird	Yes	No	No	No
flycatcher	Yes	No	No	No

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

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

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

kingbird (noun)	flycatcher (noun)
large American flycatcher	any of a large group of small songbirds that feed on insects taken on the wing
	large American birds that characteristically catch insects on the wing