Pronunciation IPA (key): /nuːn/ Audio (US)(file) Audio (UK)(file) Noun Singular noon Plural noons 12:00 PM. Synonym: midday Antonym: midnight We turned the television on just before noon. The middle of the civil day. The middle of the daytime. It's the part of the day when the sun is at its zenith. Wikiwand - on Seamless Wikipedia browsing. On steroids.Remove ads