UFO

noun

ˌyü-(ˌ)ef-ˈō 

ˈyü-(ˌ)fō

plural UFO's or UFOs ˌyü-(ˌ)ef-ˈōz 

ˈyü-(ˌ)fōz

: a mysterious flying object in the sky that is sometimes assumed to be a spaceship from another planet : unidentified flying object

"All right." The President sighed. "Is there anybody around this table who thinks UFOs and this signal from Vega have anything to do with each other?"

—Carl Sagan

In 1966, the first UFO "abduction" was described in journalist John G. Fuller's book The Interrupted Journey.

—Keay Davidson

called also UAP, unidentified aerial phenomenon, unidentified anomalous phenomenon

Examples of UFO in a Sentence

Recent Examples on the Web

The information that has been made public shows that the vast majority of UFO reports made by the military go unsolved but the ones that are identified are largely benign in nature. —Michelle L. Price, The Orlando Sentinel, 20 Feb. 2026

The federal government has also declassified and released large tranches of UFO files before. —Brett Tingley, Space.com, 20 Feb. 2026

Which states report the most UFO sightings? —Marina Johnson, Louisville Courier Journal, 16 Feb. 2026

In 2013, the CIA acknowledged the existence of the site, but not UFO crashes, black-eyed extraterrestrials or staged moon landings. —ABC News, 16 Feb. 2026

Word History

Etymology

unidentified flying object

First Known Use

1952, in the meaning defined above

Rhymes for UFO

• acknow
• aglow
• ago
• airglow
• aloe
• altho
• although
• ammo
• backflow
• backhoe
• banjo
• barbeau

Kids Definition

UFO

noun

ˌyü-(ˌ)ef-ˈō 

plural UFO's or UFOs -ˈōz 

: an unidentified flying object

especially : flying saucer