lagoon

lagoon is a   Noun

Definition:

[1] A shallow sound, channel, pond, or lake, especially one into which the sea flows; as, the lagoons of Venice.

[2] 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.

Synonyms: