Old World robin vs robin redbreast

Old World robin and robin redbreast both are nouns.

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

As nouns, Old World robin and robin redbreast are synonyms defined as:

Old World robin and robin redbreast: small Old World songbird with a reddish breast

Other synonyms of Old World robin include Erithacus rubecola, redbreast, robin.

Old World robin (noun)	robin redbreast (noun)
small Old World songbird with a reddish breast	small Old World songbird with a reddish breast