Old World robin vs thrush

Old World robin and thrush both are nouns.

Word	Noun	Adjective	Verb	Adverb
Old World robin	Yes	No	No	No
thrush	Yes	No	No	No

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

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

Old World robin (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