pet shop vs shop

pet shop and shop both are nouns.

Word	Noun	Adjective	Verb	Adverb
pet shop	Yes	No	No	No
shop	Yes	No	Yes	No

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

Other hypernyms of pet shop include store.

pet shop (noun)	shop (noun)
a shop where pet animals can be purchased	a course of instruction in a trade (as carpentry or electricity)
	a mercantile establishment for the retail sale of goods or services
	small workplace where handcrafts or manufacturing are done

pet shop (verb)	shop (verb)
	give away information about somebody
	do one's shopping
	shop around; not necessarily buying
	do one's shopping at; do business with; be a customer or client of