D defs.my
Entry 1 sense Webster, 1913

Atoll

/ăt'-älˌ/ · A·toll · IPA /ˈætɔl/
01 n. A coral island or islands, consisting of a belt of coral reef, partly submerged, surrounding a central lagoon or depression; a lagoon island.
  1. 1.
    A coral island or islands, consisting of a belt of coral reef, partly submerged, surrounding a central lagoon or depression; a lagoon island.