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)

1. Anything not readily explainable appearing to move through or be suspended in the air, primarily used to refer to objects that seem to be at least of small familiar aircraft size.

   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.

   • 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, →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.

2. (colloquial) An alien spacecraft.

   Synonym: (more commonly) UFO

• UFO (abbreviation)
• UAP, unidentified aerial phenomenon, unexplained aerial phenomenon
• (alien spacecraft): flying saucer

• flying object

• transient luminous event (“TLE”)

• unidentified flying object on Wikipedia.Wikipedia