redbreast vs Erithacus rubecola

redbreast and Erithacus rubecola both are nouns.

Word	Noun	Adjective	Verb	Adverb
redbreast	Yes	No	No	No
Erithacus rubecola	Yes	No	No	No

As nouns, redbreast and Erithacus rubecola are synonyms defined as:

redbreast and Erithacus rubecola: small Old World songbird with a reddish breast

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

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