arête

thumb|right|Striding Edge, an arête viewed from Helvellyn with the corrie [[Red Tarn to the left and Nethermost Cove to the right]]

An arête ( ; ) is a narrow ridge of rock that separates two valleys. It is typically formed when two glaciers erode parallel U-shaped valleys. Arêtes can also form when two glacial cirques erode headwards towards one another, although frequently this results in a saddle-shaped pass, called a col. The edge is then sharpened by freeze-thaw weathering, and the slope on either side of the arête steepened through mass wasting events and the erosion of exposed, unstable rock. The word arête is French for "edge" or "ridge"; similar features in the Alps are often described with the German equivalent term Grat.