/ Thesaurus / I Synonyms of isthmus of darien Find synonyms for: Noun1. Isthmus of Panama, Isthmus of Darienusage: the isthmus that connects Central America and South America; was formerly called the Isthmus of Darien; "Balboa crossed the Isthmus of Darien"WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: censure Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language