Definition of UFO noun from the Oxford Advanced Learner's Dictionary

 

UFO

 noun
(also ufo)noun
BrE BrE//ˌjuː ef ˈəʊ//
 
; NAmE NAmE//ˌjuː ef ˈoʊ//
 
; BrE BrE//ˈjuːfəʊ//
 
; NAmE NAmE//ˈjuːfoʊ//
 
(pl. UFOs, ufos)
 
jump to other results
the abbreviation for Unidentified Flying Object (a strange object that some people claim to have seen in the sky and believe is a spacecraft from another planet) compare flying saucer Word Origin 1950s: acronym from unidentified flying object.
See the Oxford Advanced American Dictionary entry: UFO