from The American Heritage® Dictionary of the English Language, 4th Edition
- n.pl. The rapids of a river that runs between the steep precipices of a gorge or narrow valley.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The rapids in a deep, narrow stream confined between the rock walls of a canyon or gorge.
- n. A steep-sided part of a stream channel, near the dalles proper, marked by clefts, ravines, or gorges.
from the GNU version of the Collaborative International Dictionary of English
- n.pl. A rapid, esp. one where the channel is narrowed between rock walls.
French, pl. of dalle, gutter, from Old French, from Old Norse dæla.(American Heritage® Dictionary of the English Language, Fourth Edition)
From the French dalle. (Wiktionary)