Lagoon-forming landform (5)
I believe the answer is:
atoll
(Other definitions for atoll that I've seen before include "Circular coral reef" , "Pacific coral island" , "Coral circle" , "tropical island" , "String of islands" .)
I believe the answer is:
atoll
(Other definitions for atoll that I've seen before include "Circular coral reef" , "Pacific coral island" , "Coral circle" , "tropical island" , "String of islands" .)