UFO

American  

[yoo-ef-oh, yoo-foh] / ˈjuˈɛfˈoʊ, ˈju 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

He said that “most of the space-focused ETFs in the market are down further than UFO over the past month, because they are concentrated around a smaller number of more volatile space stocks.”

From MarketWatch • Jun. 24, 2026

Cultural obsession with UFO conspiracies has renewed in recent years, bolstered by government initiatives and celebrity support.

From The Wall Street Journal • Jun. 18, 2026

Unlike the US, the UK currently lacks a formal, centralised system for recording or investigating UFO sightings.

From BBC • Jun. 13, 2026

Meanwhile, earlier this spring, the U.S. government declassified another batch of UFO files and the response was roughly equivalent to a collective shrug.

From Los Angeles Times • Jun. 11, 2026

Annemarie and Julia helped me install my playground on Main Street, and Julia’s UFO finally got approved by Jay Stringer.

From "When You Reach Me" by Rebecca Stead