cosmic microwave background

noun

Faint thermal radiation that pervades all space and is thought to be the remnants of the Big Bang, produced during the epoch of recombination.

“Holonyms: cosmic background, cosmic background radiation < electromagnetic radiation < radiation”

Similar
cosmic background radiationCBRcosmic microwave background radiationCMBRCMB
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Meanings

nouncosmic microwave background (uncountable, abbreviation CMB)

abbreviation CMB

  1. uncountableastronomyFaint thermal radiation that pervades all space and is thought to be the remnants of the Big Bang, produced during the epoch of recombination.

    Holonyms: cosmic background, cosmic background radiation < electromagnetic radiation < radiation

Synonyms & antonyms

noun(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

Similar
cosmic background radiationCBRcosmic microwave background radiationCMBRCMB
Broader
cosmic radiation
Also see
cosmic background radiation

Synonym sets from Open English WordNet, CC BY 4.0.

Origin

It was originally called the primeval fireball.

Full word history & related roots →

Translations

Finnish kosminen taustasäteily, avaruuden taustasäteily
  • kosminen taustasäteilyTranslations
  • avaruuden taustasäteilyTranslations
French fond diffus cosmologique
  • fond diffus cosmologiqueTranslations
Polish mikrofalowe promieniowanie tła
  • mikrofalowe promieniowanie tłaTranslations
Russian реликтовое излучение
  • реликтовое излучение (reliktovoje izlučenije)Translations
Cite this entry
APA

cosmic microwave background. (n.d.). In WatkinsX Dictionary. Retrieved November 4, 2026, from https://dictionary.watkinsx.com/word/cosmic%20microwave%20background

MLA

“cosmic microwave background.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/cosmic%20microwave%20background. Accessed November 4, 2026.

Chicago

WatkinsX Dictionary, s.v. “cosmic microwave background,” accessed November 4, 2026, https://dictionary.watkinsx.com/word/cosmic%20microwave%20background.

Source: cosmic microwave background on Wiktionary, CC BY-SA 4.0.