a lake of salt water that is separated from the sea by a reef or an area of rock or sand 潟湖；环礁湖；濒海湖 - (North American English)
a small area of fresh water near a lake or river （湖泊或江河附近的）小片淡水域，小淡水湖 We loved to go swimming in the lagoon. 我们喜欢到小淡水湖里去游泳。
- (specialist)
an artificial area built to hold waste water before it is treated at a sewage works 氧化塘
Word Originearly 17th cent.: from Italian and Spanish laguna, from Latin lacuna ‘pool’, from lacus ‘lake’.