noun
- a ring-shaped coral reef or chain of coral islands surrounding a lagoon
Examples
- The Maldives consists of many beautiful atolls in the Indian Ocean.
- Scientists studied the coral growth on the remote atoll.
- The plane flew over a perfect circular atoll with crystal-clear water in the center.
- Many Pacific atolls are threatened by rising sea levels.
- The atoll’s lagoon provided a safe harbor for the sailing expedition.
- Bikini Atoll was used for nuclear testing in the 1940s and 1950s.