geographic circque

A deep steep-walled half-bowl-like recess or hollow, variously described as horseshoe- or crescent-shaped or semi-circular in plan, situated high on the side of a mountain and commonly at the head of a glacial valley and produced by the erosive activity of a mountain glacier. It often contains a small round lake, and it may or may not be occupied by ice or snow. (Source: BJGEO)