redbreast vs thrush

redbreast and thrush both are nouns.

Word	Noun	Adjective	Verb	Adverb
redbreast	Yes	No	No	No
thrush	Yes	No	No	No

As nouns, thrush is a hypernym of redbreast; that is, thrush is a word with a broader meaning than redbreast:

redbreast: small Old World songbird with a reddish breast
thrush: songbirds characteristically having brownish upper plumage with a spotted breast

redbreast (noun)	thrush (noun)
small Old World songbird with a reddish breast	songbirds characteristically having brownish upper plumage with a spotted breast
	a woman who sings popular songs
	candidiasis of the oral cavity; seen mostly in infants or debilitated adults