unidentified flying object

IPA/ʌn.aɪˌden.tɪ.faɪd ˌflaɪ.ɪŋ ˈɒb.dʒekt/
IPA/ʌn.aɪˌden.t̬ə.faɪd ˌflaɪ.ɪŋ ˈɑːb.dʒekt/

unidentified flying object — noun

1. an object seen moving through the air that nobody can explain, and that some peo

1.nounB1
Definition

an object seen moving through the air that nobody can explain, and that some people imagine could be a spaceship from beyond our planet

Example

Grandpa claims he saw an unidentified flying object above the barn last night.

simple past with personal anecdote

A pilot reported an unidentified flying object on the radar screen over Mexico.

professional context: pilot + radar

Common collocations
  • sighting of an unidentified flying object
  • report an unidentified flying object
  • photograph of an unidentified flying object
  • witness to an unidentified flying object
Synonyms
  • UFO

    the common abbreviation; used in everyday speech and news headlines

  • flying saucer

    older, more informal term that suggests a disc-shaped alien craft; less common today

  • UAP

    modern official term used by military and government agencies; broader scope

Usage Note

often abbreviated as UFO (pronounced as separate letters or as a word). The full form "unidentified flying object" is more common in formal or written contexts, while "UFO" is the usual casual spoken form used in everyday conversation and media. In official or scientific contexts, the newer term UAP (unidentified aerial phenomenon) is increasingly preferred.

Common Mistakes

I saw an unidentified flying object — it was clearly a drone.
I saw an unidentified flying object
I could not tell whether it was a drone or a bird.' — If you can identify the object, it is not an unidentified flying object.

Word family

Synonym discussion

Sense: noun/1

UFO is the most common abbreviation of unidentified flying object and is used everywhere from casual conversation to news headlines. Flying saucer is an older, more playful term that became popular in the 1950s after a pilot described nine disc-shaped objects as 'flying saucers'; it strongly suggests an alien spaceship and sounds dated or informal today. UAP (unidentified aerial phenomenon) is the term now used by the US military and aviation authorities; it covers objects that may not be 'flying' in the usual sense (e.g., hovering or underwater). A news headline might read 'Pilot reports UFO over Arizona,' while a government document would say 'UAP investigation launched.'

UFOflying saucer ↗UAP

Common collocations

Nouns

Phrases

  • an unidentified flying object

Prepositions

  • of (sighting of)
  • about (report about)
  • on (photograph on)

Etymology

English

The term unidentified flying object was created by the United States Air Force in the early 1950s as a formal, neutral replacement for the informal term flying saucer. The abbreviation UFO appeared soon after and became widely used in popular culture.

First known use

1947

1947, in the meaning defined above