/ Thesaurus / C Synonyms of charles river Find synonyms for: Noun1. Charles, Charles Riverusage: a river in eastern Massachusetts that empties into Boston Harbor and that separates Cambridge from BostonWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: devout Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language