- A ring-shaped reef, island, or chain of islands formed of coral.More example sentences
- The islands of the Maldives are grouped in ring-shaped coral atolls, each enclosing a relatively shallow lagoon with a flat sandy bottom.
- The Marshall Islands are a group of low-lying coral atolls and islands in the central Pacific Ocean.
- Tuvelu is one of the smallest countries on earth, a chain of nine coral atolls whose highest point is just a few meters above sea level.
early 17th century: from Maldivian atoḷu.
More definitions of atollDefinition of atoll in:
- The US English dictionary