valley A depression caused by erosion by water or ice. Low-lying land bordered by higher ground; especially elongate, relatively large gently sloping depressions of the Earth's surface, commonly situated between two mountains or between ranges of hills or mountains, and often containing a stream with an outlet. ENVO ENVO:00000100 EcoLexicon:valley FTT:158 FTT:166 FTT:418 FTT:761 FTT:811 FTT:949 Geonames:T.GRGE Geonames:T.VAL Geonames:T.VALS SWEETRealm:Valley TGN:21425 TGN:21451 TGN:21452 TGN:21453 VALLEY Wikipedia:Valley chasm coulee dale glacial gorge glacial trough glen goe gorge graben gulch gully hollow lavaka median valley moat ravine re-entrant seachannel shelf valley strath trench vale valley valleys water gap depression