unidentified anomalous phenomenon
noun
plural unidentified anomalous phenomena
: a mysterious phenomenon (especially an unidentified aerial phenomenon) that is sometimes assumed to be a spaceship from another planet : uap
—used especially as an alternative to UFO or unidentified flying object
Unidentified anomalous phenomena, or UAP, "are events in the sky that cannot be identified as aircraft or known natural phenomena from a scientific perspective," according to NASA. The term UAP, originally meaning unidentified aerial phenomena, was changed by the National Defense Authorization Act, which was signed into law in December, [Dan] Evans said. The change occurred in recognition of the fact that the search for UAP should include near space and undersea phenomena as well, he said.—Ashley Strickland
The director of the Pentagon's new UFO office shot down hopes that the buzz over unidentified anomalous phenomena (UAP) supports claims of extraterrestrial visitation.—Brett Tingley
Cite this Entry
“Unidentified anomalous phenomenon.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/unidentified%20anomalous%20phenomenon. Accessed 12 Aug. 2026.
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