Lagoon

n. shallow body of water which is cut of from the sea by sand dunes; pond, small body of water (especially one which is connected to a larger body of water)

This article is about natural lagoons. For other uses of lagoon, please see Lagoon (disambiguation). A lagoon is a body of comparatively shallow salt or brackish water separated from the deeper sea by a shallow or exposed sandbank, coral reef, or similar feature. Thus, the enclosed body of water behind a barrier reef or barrier islands or enclosed by an atoll reef is called a lagoon. This application of lagoon in English dates from 1769. It adapted and extended the sense of the Venetian laguna (cf Latin , 'empty space'), which specifically referred to Venice's shallow, island-studded stretch of saltwater, protected from the Adriatic by the barrier beaches of the Lido (see Venetian Lagoon). Lagoon refers to both coastal lagoons formed by the build-up of sandbanks or reefs along shallow coastal waters, and the lagoons in atolls, formed by the growth of coral reefs on slowly sinking central islands. Lagoons that are fed by freshwater streams are also called estuaries.
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Noun
1. a body of water cut off from a larger body by a reef of sand or coral
(synonym) laguna, lagune
(hypernym) lake
(hyponym) liman

(n.)
A shallow sound, channel, pond, or lake, especially one into which the sea flows; as, the lagoons of Venice.
  

(n.)
A lake in a coral island, often occupying a large portion of its area, and usually communicating with the sea. See Atoll.
  

(See also Lake, Levee) A shallow area of salt water separated from the open sea by sand or shingle banks. The sheet of water between an offshore reef, especially of coral, and the mainland. The sheet of water within a ring or horseshoe-shaped atoll. (DOI4)