/ Thesaurus / S Synonyms of single supplement Find synonyms for: Noun1. single supplement, surchargeusage: a surcharge added to the cost per person when traveling aloneWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: illegible Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language