unexplained aerial phenomenon

Noun

unexplained aerial phenomenon (plural unexplained aerial phenomena)

1. Synonym of unidentified aerial phenomenon (“UAP”).
   • During World War II (and probably before), high flying pilots were reported to have observed unexplained aerial phenomena (UAP), often now called transient luminous events (TLE’s), particularly in the vicinity of thunderstorms.2012, Don Lipman, The Washington Post, "Red sprites, blue jets, and elves What are these mysterious, elusive phenomena?"
   • “You know, there’s a new name,” Mrs. Clinton said in the March appearance. “It’s unexplained aerial phenomenon,” she said. “U.A.P. That’s the latest nomenclature.”2016, Amy Chozick, The New York Times, "Hillary Clinton Gives U.F.O. Buffs Hope She Will Open the X-Files"

   Synonyms:

   unidentified aerial phenomenon