/ Thesaurus / D Synonyms of drainage basin Find synonyms for: Noun1. river basin, basin, watershed, drainage basin, catchment area, catchment basin, drainage area, geographical area, geographic area, geographical region, geographic regionusage: the entire geographical area drained by a river and its tributaries; an area characterized by all runoff being conveyed to the same outlet; "flood control in the Missouri basin"WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: blithesome Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language