common pepper vs Piper nigrum

common pepper and Piper nigrum both are nouns.

Word	Noun	Adjective	Verb	Adverb
common pepper	Yes	No	No	No
Piper nigrum	Yes	No	No	No

As nouns, common pepper and Piper nigrum are synonyms defined as:

common pepper and Piper nigrum: climber having dark red berries (peppercorns) when fully ripe; southern India and Sri Lanka; naturalized in northern Burma and Assam

Other synonyms of common pepper include black pepper, Madagascar pepper, pepper, white pepper.

common pepper (noun)	Piper nigrum (noun)
climber having dark red berries (peppercorns) when fully ripe; southern India and Sri Lanka; naturalized in northern Burma and Assam	climber having dark red berries (peppercorns) when fully ripe; southern India and Sri Lanka; naturalized in northern Burma and Assam