UFO

American  

[yoo-ef-oh, yoo-foh] / ˈyuˈɛfˈoʊ, ˈyu foʊ /

abbreviation

plural

UFO's, UFOs

1. unidentified flying object: any unexplained moving object observed in the sky, especially one assumed by some observers to be of extraterrestrial origin.

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UFO British  

/ ˈjuːfəʊ /

abbreviation

1. unidentified flying object

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UFO ¹ Cultural  

1. The abbreviation for u nidentified f lying o bject. Sometimes referred to colloquially as “flying saucers.” Most UFO sightings have prosaic explanations; there is no hard evidence that extraterrestrial beings are visiting Earth.

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UFO ² Cultural  

1. An abbreviation for “U nidentified F lying O bject.” Often described as “flying saucers,” some UFOs are believed to come from other planets or galaxies and thus support the idea that human beings are not the only form of intelligent life in the universe. Few scientists agree.

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Usage

See UAP.

Etymology

Origin of UFO

First recorded 1950–55

Example Sentences

UFO cabin crew also walked out on Friday at both Lufthansa and CityLine in a dispute over working conditions.

From Barron's • Apr. 13, 2026

Brazil’s UFO capital marks 30 years since alleged alien encounter.

From MarketWatch • Mar. 24, 2026

After breaking through into the Wasps team, French selectors applied another three-letter moniker to Flament, describing him as a UFO, such was his sudden, unexpected appearance on their radar.

From BBC • Feb. 26, 2026

But the agency did discover that a network of UFO believers within the Defense Department had created a program that investigated accounts of interdimensional creatures and werewolves on a ranch in Utah.

From The Wall Street Journal • Feb. 22, 2026

If their UFO keys fall off the console—boom!—instant arm.

From "We Are the Ants" by Shaun David Hutchinson