pilchard vs Sardina pilchardus

pilchard and Sardina pilchardus both are nouns.

Word	Noun	Adjective	Verb	Adverb
pilchard	Yes	No	No	No
Sardina pilchardus	Yes	No	No	No

As nouns, pilchard and Sardina pilchardus are synonyms defined as:

pilchard and Sardina pilchardus: small fishes found in great schools along coasts of Europe; smaller and rounder than herring

Other synonyms of pilchard include sardine.

pilchard (noun)	Sardina pilchardus (noun)
small fishes found in great schools along coasts of Europe; smaller and rounder than herring	small fishes found in great schools along coasts of Europe; smaller and rounder than herring
small fatty fish usually canned