A mountain pool that forms in a hollow scooped out by a glacier is called a tarn. Officially, tarns are smaller than lakes.
Another name for a tarn is a corrie loch, from the Scottish Gaelic coire, or "pot," and loch, "lake." These glacier-formed pools are found all over the world, from New York's Adirondack Mountains to the Tatras Mountains in Slovakia. The word tarn comes from the Old Norse tjörn, "small mountain lake with no tributaries."