pea vs marrowfat pea

pea and marrowfat pea both are nouns.

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

As nouns, marrowfat pea is a hyponym of pea; that is, marrowfat pea is a word with a more specific, narrower meaning than pea:

pea: seed of a pea plant used for food
marrowfat pea: a variety of large pea that is commonly processed and sold in cans

Other hyponyms of pea include garden pea, green pea, cajan pea, dahl, pigeon pea, field pea.

pea (noun)	marrowfat pea (noun)
seed of a pea plant used for food	a variety of large pea that is commonly processed and sold in cans
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