tyrant bird vs pewit

tyrant bird and pewit both are nouns.

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

As nouns, pewit is a hyponym of tyrant bird; that is, pewit is a word with a more specific, narrower meaning than tyrant bird:

tyrant bird: large American birds that characteristically catch insects on the wing
pewit: small olive-colored woodland flycatchers of eastern North America

tyrant bird (noun)	pewit (noun)
large American birds that characteristically catch insects on the wing	large crested Old World plover having wattles and spurs
	small olive-colored woodland flycatchers of eastern North America
	small black-headed European gull