“UAP” replaced “UFO” in official U.S. usage to strip decades of stigma and broaden the category; the 2023 defense bill formalized “unidentified anomalous phenomena,” covering objects in the air, in space, and underwater.
U.S. Navy reporting guidance (2019–2020), the ODNI's 2021 report to Congress, and Congress itself in successive defense bills; the Pentagon's investigating office — AARO — carries the term in its name.
Pilots will file a “UAP” report where a “UFO” report would have cost them credibility. “UFO” had come to mean “alien spacecraft” — which is a conclusion. “Unidentified” is an observation.
“UAP” is the official term across the U.S. government; “UFO” survives in common speech, and both mean the same thing: we don't know what it was.
The Air Force coined “unidentified flying object” in 1952 for Project Blue Book, precisely because the popular term of the day — “flying saucer” — presumed a shape and an answer. It was a sober term. Seventy years of culture made it the opposite: by the 2000s, “UFO” meant little green men, and a military aviator who used the word on the record was gambling with a career.
The rename happened in stages, and each stage is a document you can read. In 2019 the Navy issued new reporting guidance for its pilots and began saying “unidentified aerial phenomena.” In June 2021, the ODNI's preliminary assessment to Congress used UAP throughout. In 2022 the Pentagon stood up the All-domain Anomaly Resolution Office, and Congress — noting reports of objects that moved between air and water — swapped “aerial” for “anomalous,” expanding the category to all domains.
The point of the new term is the point of this site: separate the observation from the conclusion. Something unidentified crossed a sensor. That is the fact. What it was is the question — and the reason the file stays open.
AP PRESS