atoll
US /ˈæt.ɑːl/
UK /ˈæt.ɑːl/
1.
a ring-shaped coral reef or island or a string of coral islands enclosing a shallow lagoon
:
•
The divers explored the vibrant marine life around the atoll.
•
Many Pacific islands are formed by atolls.
a ring-shaped coral reef or island or a string of coral islands enclosing a shallow lagoon