lagoon A sheet of saline water separated from the open sea by sand or shingle banks. The sheet of water between an offshore reef, especially of coral and mainland. The sheet of water within a ring or horseshoe shaped atoll. ENVO ENVO:00000038 EcoLexicon:lagoon FTT:221 FTT:898 FTT:899 Geonames:H.LGN Geonames:H.LGNS LAGOON Lagoon SWEETRealm:Lagoon TGN:21125 Wikipedia:Lagoon barrier lagoon lagoon lagoons laguna lake coastal wetland