common pea vs pea

common pea and pea both are nouns.

Word	Noun	Adjective	Verb	Adverb
common pea	Yes	No	No	No
pea	Yes	No	No	No

As nouns, pea is a hypernym of common pea; that is, pea is a word with a broader meaning than common pea:

common pea: plant producing peas usually eaten fresh rather than dried
pea: a leguminous plant of the genus Pisum with small white flowers and long green pods containing edible green seeds

Other hypernyms of common pea include pea plant.

common pea (noun)	pea (noun)
plant producing peas usually eaten fresh rather than dried	seed of a pea plant used for food
	a leguminous plant of the genus Pisum with small white flowers and long green pods containing edible green seeds
	the fruit or seed of a pea plant