from The American Heritage® Dictionary of the English Language, 4th Edition
- n. An area drained by a river system.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A topographic region in which all water drains to a common outlet; a watershed.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. the entire geographical area drained by a river and its tributaries; an area characterized by all runoff being conveyed to the same outlet
Sorry, no etymologies found.
He looked out across the drainage basin and saw a sea of bluestem grass—a valley grass.