A horn is a glacial landform that develops when at least three glaciers carve away the surface of a single mountain top. This geological structure is characterized by steep sloping sides and a sharp-edged summit.
Glaciers are massive layers of ice that gradually move over land areas, such as mountain valleys. The glaciation process usually involves the formation of prominent mountain features, which include aretes and horns.
Aretes develop when two glaciers sharply erode the opposite sides of a long narrow hilltop. Horns, meanwhile, are created when three or more glaciers act on an arete to form a mountain peak. Two examples of glacial horns include Kinnerly Peak in the United States and Matterhorn in Switzerland.