A deep, steep-walled, half-bowllike recess or hollow situated high on the side of a mountain and commonly at the head of a glacial valley; and produced by the erosive activity of mountain glaciers.
CIRQUE

A deep, steep-walled, half-bowllike recess or hollow situated high on the side of a mountain and commonly at the head of a glacial valley; and produced by the erosive activity of mountain glaciers.