Huge self-service store (11)

I believe the answer is:

hypermarket

(Other definitions for hypermarket that I've seen before include "Enormous shop" , "Very large self-service store" , "Big out-of-town shop" , "Vast shop" , "Super-superstore" .)

I've seen this clue in The Mirror.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.