/ Thesaurus / E Synonyms of extensively Find synonyms for: Adverb1. extensivelyusage: in a widespread way; "oxidation ponds are extensively used for sewage treatment in the Midwest"WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: inutiae Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language