from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Chiefly Southwestern U.S. A flat arid valley surrounded by mountains and draining into a shallow central lake.
from The Century Dictionary and Cyclopedia
- n. In physical geography, a basin-shaped depression inclosed on nearly all sides by mountains.
American Spanish bolsón, augmentative of Spanish bolsa, purse, pouch, from Late Latin bursa; see bursa.(American Heritage® Dictionary of the English Language, Fourth Edition)