pollack vs Pollachius pollachius

pollack and Pollachius pollachius both are nouns.

Word	Noun	Adjective	Verb	Adverb
pollack	Yes	No	No	No
Pollachius pollachius	Yes	No	No	No

As nouns, pollack and Pollachius pollachius are synonyms defined as:

pollack and Pollachius pollachius: important food and game fish of northern seas (especially the northern Atlantic); related to cod

Other synonyms of pollack include pollock.

pollack (noun)	Pollachius pollachius (noun)
important food and game fish of northern seas (especially the northern Atlantic); related to cod	important food and game fish of northern seas (especially the northern Atlantic); related to cod
lean white flesh of North Atlantic fish; similar to codfish