discount store vs sales outlet

discount store and sales outlet both are nouns.

Word	Noun	Adjective	Verb	Adverb
discount store	Yes	No	No	No
sales outlet	Yes	No	No	No

As nouns, sales outlet is a hypernym of discount store; that is, sales outlet is a word with a broader meaning than discount store:

Other hypernyms of discount store include mercantile establishment, outlet, retail store.

discount store (noun)	sales outlet (noun)
a sales outlet offering goods at a discounted price	a place of business for retailing goods