/ Thesaurus / C Synonyms of cmbr Find synonyms for: Noun1. cosmic background radiation, CBR, cosmic microwave background radiation, CMBR, cosmic microwave background, CMB, cosmic radiationusage: (cosmology) the cooled remnant of the hot big bang that fills the entire universe and can be observed today with an average temperature of about 2.725 kelvinWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: reticent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language