Atoll

n.

1.

A coral island or islands, consisting of a belt of coral reef, partly submerged, surrounding a central lagoon or depression; a lagoon island.

Noun

1.

atoll - an island consisting of a circular coral reef surrounding a lagoon

ATOLL - Acceptance, Test Or Launch Language

ait, archipelago, bar, cay, continental island, coral head, coral island, coral reef, holm, insularity, island, island group, islandology, isle, islet, key, oceanic island, reef, sandbank, sandbar