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.

---

UFO British  

/ ˈjuːfəʊ /

abbreviation

1. unidentified flying object

---

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.

---

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.

---

Usage

See UAP.

Etymology

Origin of UFO

First recorded 1950–55

Example Sentences

A particularly intriguing chapter in Hill's back story is her link to one of the most famous episodes in UFO folklore.

From Barron's • May 29, 2026

The Pentagon released scores of UFO files on Friday with descriptions of reported sightings of orbs, discs and fireballs spanning 80 years.

From BBC • May 22, 2026

To see just how far ETFs have drifted from the investment mainstream, look at the Tuttle Capital UFO Disclosure ETF.

From The Wall Street Journal • May 22, 2026

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

He quickly found the more arcane sites: alien abduction, UFO sightings, and the supernatural.

From "Artemis Fowl" by Eoin Colfer