A cirque is a bowl-shaped, amphitheater-like depression eroded into a mountain by a glacier. Cirques are typically found at the head of a glacial valley and are the starting point for glacier formation. The study of cirques is important in understanding glacial processes, alpine geomorphology, and the climatic conditions that lead to glacier formation.
Reference: Benn, D. I., & Evans, D. J. A. (2010). Glaciers and Glaciation. Routledge.