dalle n.

the source of The Dalles, city name in Oregon, U.S., from dalle, the name given by French employees of the Hudson's Bay Company and its successors to certain situations of rivers, the best-known being the one on the Columbia River that gives the city its name. The French word might be a reference to trough-like channels, from Low German or Dutch daal "outlet, drain," or it might be from a different but identical word meaning "slab or large tile of stone."