pet food vs feed

pet food and feed both are nouns.

Word	Noun	Adjective	Verb	Adverb
pet food	Yes	No	No	No
feed	Yes	No	Yes	No

As nouns, feed is a hypernym of pet food; that is, feed is a word with a broader meaning than pet food:

Other hypernyms of pet food include provender.

pet food (noun)	feed (noun)
food prepared for animal pets	food for domestic livestock

pet food (verb)	feed (verb)
	provide with fertilizers or add nutrients to
	introduce continuously
	take in food; used of animals only
	give food to
	serve as food for; be the food for
	feed into; supply
	provide as food
	gratify
	profit from in an exploitatory manner
	move along, of liquids
	support or promote