CBR uncommon noun 1. (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 kelvin Synonymscosmic background radiationcosmic microwave background radiationCMBRcosmic microwave backgroundCMB Related words Broader terms cosmic radiation WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.
