bikini atoll
a group of small coral islands in the shape of a ring that encloses a lagoon
the oppsite of atoll is planet
An atoll is formed first as a reef that fringes a volcanic island. As the island sinks (after the volcanic activity has ceased and the crust has cooled, becoming denser), the reef continues to build upward, eventually ending up as a ring-shaped structure.
Allot and atoll.
bikini atoll
Atoll is a noun.
A atoll
The population of Namu Atoll is 801.
Ailinginae Atoll's population is 0.
Midway Atoll was created in 1988.
The population of Rongelap Atoll is 19.
Utirik Atoll's population is 409.