noun.
An area of shallow water, or even of marshy land, bordering on the sea, and usually separated from the region of deeper water outside by a belt of sand or of sand-dunes, more or less changeable in position.
noun.
With reference to Tuscany and some other parts of Italy, the basin of a hot spring, especially one from which borax is obtained: from the Italian use of lagone in this sense.
noun.
In occasional use, the area of still water inclosed within an atoll, which is often called a lagoon island. See atoll.