Coral formation surrounding a lagoon (5)

I believe the answer is:

atoll

(Other definitions for atoll that I've seen before include "Ring of coral" , "Ring-shaped coral island" , "tropical paradise?" , "Bikini, say" , "Pacific coral island" .)

I've seen this clue in The Times.

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.