Definition

Noun: An (apparently) flying object whose nature is unknown; especially those considered to have extraterrestrial origins. It refers to any aerial phenomenon or object that cannot be immediately identified by the observer.

Usage

The term "unidentified flying object" is used to describe a sighting of an object in the sky that the witness cannot recognize. It is a formal and neutral term, often used in official reports, scientific discussions, and news media. The abbreviation "UFO" is extremely common in everyday language.

Examples

• The pilot reported seeing an unidentified flying object that moved at incredible speed.
• Many reports of unidentified flying objects from the 1950s were later explained as weather balloons or experimental aircraft.
• The government declassified files on unidentified flying objects.

Advanced Usage

• "UFO" as a common noun: When the abbreviation is so prevalent, it is often treated as a standard noun (e.g., "a UFO," "several UFOs").
  • He claimed to have photographed a UFO over the desert.
• In official and scientific contexts: The term is increasingly being replaced or supplemented by more precise terminology like "Unidentified Aerial Phenomena (UAP)" to emphasize the unknown nature of the event rather than assuming it is a physical "object."

Variants and Related Words

• UFO (n.): The standard abbreviation for "unidentified flying object."
• UAP (Unidentified Aerial Phenomenon) (n.): A more modern term often used in official government and scientific contexts to describe a wider range of unexplained observations in the sky, including those detected by sensors without a visual sighting.
• Flying saucer (n.): A dated and informal term for a UFO, specifically describing a disc- or saucer-shaped craft. This term carries stronger connotations of extraterrestrial origin.

Synonyms

• Flying saucer (informal, specific shape implied)
• Unknown aerial vehicle (formal, technical)

Related Idioms and Phrases

• To see a UFO: To witness an unidentified flying object. This phrase is used literally.
  • They swore they saw a UFO last night.
• UFO sighting: The event or instance of observing a UFO.
  • There was a wave of UFO sightings reported across the county.

Noun

1. an (apparently) flying object whose nature is unknown; especially those considered to have extraterrestrial origins