The Collaborative International Dictionary
lagoon \la*goon"\ (l[.a]*g[=oo]n"), n. [It. or Sp. laguna, L. lacuna ditch, pool, pond, lacus lake. See Lake, and cf. Lacuna.] [Written also lagune.]
A shallow sound, channel, pond, or lake, especially one into which the sea flows; as, the lagoons of Venice.
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A lake in a coral island, often occupying a large portion of its area, and usually communicating with the sea. See Atoll.
Lagoon island, a coral island consisting of a narrow reef encircling a lagoon.
Wikipedia
Lagoon Island is the northernmost of the Léonie Islands, lying in the entrance to Ryder Bay on the southeast side of Adelaide Island, Antarctica. It was discovered by the French Antarctic Expedition, 1908–10, under Jean-Baptiste Charcot. The island was charted by the British Graham Land Expedition under John Rymill in February 1936 and was so named because with the island on its west side it forms a lagoon.
Usage examples of "lagoon island".
Dusk was setting in, and we profited by what remained of daylight to eat our small portions of the half-dressed birds left over from those obtained on Lagoon Island.