meal vs pea flour

meal and pea flour both are nouns.

Word	Noun	Adjective	Verb	Adverb
meal	Yes	No	No	No
pea flour	Yes	No	No	No

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

meal: coarsely ground foodstuff; especially seeds of various cereal grasses or pulse
pea flour: meal made from dried peas

meal (noun)	pea flour (noun)
the food served and eaten at one time	meal made from dried peas
coarsely ground foodstuff; especially seeds of various cereal grasses or pulse
any of the occasions for eating food that occur by custom or habit at more or less fixed times