la·goon n. [Written also lagune.]
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.
n : a body of water cut off from a larger body by a reef of sand
or coral [syn: laguna, lagune]