n. 1 a stretch of salt water separated from the sea by a low sandbank, coral reef, etc. 2 the enclosed water of an atoll. 3 US, Austral., & NZ a small freshwater lake near a larger lake or river. 4 an artificial pool for the treatment of effluent or to accommodate an overspill from surface drains during heavy rain.
[ F lagune or It. & Sp. laguna f. L lacuna: see LACUNA ]