unidentified flying object

The phrase is usually attributed to US Air Force officer Edward J. Ruppelt (1923–1960) who coined it as a replacement of the terms flying saucer and flying disk.

unidentified flying object (plural unidentified flying objects)

2. Anything not readily explainable appearing to move through or be suspended in the air.

   The lights seen over the city last night, originally termed unidentified flying objects, turned out to be spotlights from a car dealership reflecting on low clouds.

   Synonyms: UFO, UAP, unidentified aerial phenomenon, unexplained aerial phenomenon

   Coordinate terms: TLE (“transient luminous event”) (sky); USO (“unidentified submerged object”) (water)

   1. (especially and originally) Such things as seem to be discrete objects and comparable to aircraft.

      She said that the unidentified flying object then turned around, zoomed to a higher altitude, and loitered briefly before speeding off.

      Hypernyms: UAP, unidentified aerial phenomenon, unexplained aerial phenomenon

      • 2023 February 12, Julian E. Barnes, Helene Cooper, Edward Wong, “What’s Going On Up There? Theories but No Answers in Shootdowns of Mystery Craft.”, in The New York Times‎^[1], →ISSN:

        The U.S. and Canada are investigating three unidentified flying objects shot down over North America in the past three days. Militaries have adjusted radars to try to spot more incursions.

3. (colloquial) An alien spacecraft.

   Hypernyms: spacecraft < craft, vessel, vehicle

   Hyponyms: flying saucer, flying disk

   He said that the strange beings then took him aboard their unidentified flying object and examined his body.

• unidentified flying object on Wikipedia.Wikipedia