UFO

American  

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

abbreviation

UFO's, plural UFOs plural

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

If Spielberg’s earlier UFO movies gave us awe, comfort and catastrophe, this one feels like an encounter of a fourth kind: What happens when the cover story breaks?

From Los Angeles Times • May 14, 2026

UFO is just one of several ETFs catered to the business of space.

From Barron's • May 11, 2026

Some within the UFO community believe information will be doubted no matter who releases it.

From BBC • May 8, 2026

Waiting for answers since she was a child and her mother swore she saw a UFO, Loperena is still more than enthused about the government's decision to make the release.

From BBC • May 8, 2026

They stared at me like I was Bigfoot or a UFO.

From "The Absolutely True Diary of a Part-Time Indian" by Sherman Alexie