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

Those who cast a casual early evening gaze toward Sirius these next couple of weeks might mistake it for a distant drone or even a UFO. —Joe Rao, Space.com, 25 Apr. 2025

The Green Ray This East Nashville indie bookstore features a mural of a UFO on the side. —Eva Fedderly, Architectural Digest, 18 Apr. 2025

The incident drew national attention in 2017, exposing previously unknown programs within the Department of Defense relating to UFO research. —Julia Bonavita, FOXNews.com, 17 Apr. 2025

The firsthand report describes a retaliatory alien attack after Soviet soldiers reportedly shot down a UFO flying over a military base. —Julia Bonavita, FOXNews.com, 13 Apr. 2025

Word History

Etymology

unidentified flying object

First Known Use

1953, 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