cirque

Latin circus meant "ring" or "circular arena," from Greek kirkos, "circle." French inherited it as cirque, keeping the sense of a circular enclosure. In 1830, the Cirque Olympique opened on the Boulevard du Temple in Paris—a circular theater for equestrian performances. The word meant a round space designed for spectacle.

French geologists working in the Pyrenees in the early 19th century noticed bowl-shaped hollows carved into mountainsides—steep-walled, semicircular amphitheaters open on one side, often containing a small lake. They called them cirques. The Cirque de Gavarnie in the French Pyrenees, a natural amphitheater 1,500 meters wide with a 422-meter waterfall, became the type example. Victor Hugo called it "the Colosseum of nature."

Glaciers create cirques through a process called nivation and glacial plucking. Snow accumulates in a hollow, compacts into ice, and the ice freezes to the bedrock beneath it. As the glacier moves downhill, it pulls rock fragments away from the headwall—steepening and deepening the hollow over thousands of years. When the glacier melts, it leaves a cirque: a theater with no performer, an arena abandoned by its sculptor.

Cirques are found on every continent with mountains. Cwm (pronounced "koom") is the Welsh equivalent—the Western Cwm on Everest is one of the most famous. Corrie is the Scottish Gaelic version. Kar is the German term. Each language named the same glacial landform independently. The French word won in international geological usage because French geologists described it first.