UAP

Unidentified Anomalous Phenomena (formerly Unidentified Aerial Phenomena) — the U.S. government's preferred term for what was historically called UFOs, deliberately broader to include maritime, space, and transmedium objects.

UAP stands for Unidentified Anomalous Phenomena. The acronym is the U.S. government’s preferred term, since 2022, for the category of observed objects and events historically called UFOs. The acronym is the same; the underlying definition has been expanded twice in eight years to reflect what the institutional record actually contains.

This entry traces the evolution of the term, explains how it is used operationally by AARO, distinguishes UAP from UFO in current Council practice, and clarifies what the word “anomalous” does — and does not — mean.

Definition and etymology

“UFO” — Unidentified Flying Object — was coined by the U.S. Air Force in 1953 as a Cold War operational term, drawn from the Project Blue Book era. It carried no judgment about origin: an “unidentified” object simply meant one the Air Force could not attribute to a known platform. Over the subsequent four decades, the term migrated from institutional briefings into popular culture, where it acquired the cultural baggage that “extraterrestrial” assumptions create.

In 2019, the U.S. Navy issued internal guidance using Unidentified Aerial Phenomena in place of UFO in pilot reporting. The change was deliberate. Navy aviators had been reporting unfamiliar objects during training operations off the Atlantic and Pacific coasts since at least 2014, and naval leadership concluded that the cultural associations of “UFO” suppressed reporting from pilots who feared career consequences. UAP was the destigmatized replacement.

The 2021 ODNI Preliminary Assessment — produced by the Office of the Director of National Intelligence at congressional request — adopted UAP as the formal interagency term. In that document, UAP referred specifically to airborne objects of unknown origin observed by military sensors and personnel.

In 2022, the National Defense Authorization Act created AARO and simultaneously redefined UAP as Unidentified Anomalous Phenomena. The acronym was preserved; the meaning broadened. “Anomalous” replaced “Aerial” to incorporate phenomena observed across four operational domains — airborne, maritime, space, and transmedium, the technical term for objects transitioning between air and water.

Why the term change matters

The 2019 and 2022 changes are not cosmetic. Each reflects an institutional concession about what the existing record contains.

The 2019 Aerial shift acknowledged that the reporting category was real. Before the Navy’s internal guidance, pilot reports of unfamiliar craft were filed informally or not at all. By naming UAP as a reportable category with its own intake process, the Navy converted anecdotal observations into a structured operational dataset.

The 2022 Anomalous expansion acknowledged that the data was not confined to the air. Specific cases — the USS Omaha 2019 encounter, in which an object entered the ocean without an apparent splash; the 2013 Aguadilla CBP infrared video, showing apparent transmedium behavior off Puerto Rico; reported anomalies observed from orbit by ISS crew — did not fit the “aerial” framing. AARO needed terminology consistent with its full statutory caseload.

The shift therefore reflects something more substantive than rebranding. The official language is now structured to admit the phenomena, not to filter them out.

How AARO uses the term operationally

AARO — the All-Domain Anomaly Resolution Office, established within the DoD in 2022 — is the agency now responsible for receiving, investigating, and adjudicating UAP reports across the U.S. national security apparatus. Its operational use of the term has three structural features.

Four domains. AARO categorizes every report by its primary observational domain: air, maritime, space, or transmedium. The transmedium category is the analytically distinctive one — an object that moves from air to water, or water to air, without the kinematic signature of a conventional vehicle is, by definition, not explicable as a known platform.

Workflow. A UAP report enters AARO through one of three primary channels: (1) the military reporting chain (a pilot files through their squadron, which flows upward through the relevant service branch to AARO); (2) the whistleblower mechanism established under the FY2024 NDAA, which allows current and former U.S. government personnel with first-hand knowledge to submit reports protected from retaliation; or (3) interagency referral from another federal entity. Civilian reports are not within AARO’s intake scope — those are routed to organizations like NUFORC.

Adjudication outcomes. AARO’s published reports — most recently the AARO FY2025 Report — categorize closed cases as resolved (attributed to a conventional cause, including balloons, drones, optical artifacts, and sensor anomalies) or unresolved. AARO has explicitly stated that “unresolved” does not mean extraterrestrial. It means the available evidence is insufficient to attribute the object to a known cause.

This is the critical distinction the institutional language is built to preserve.

UAP vs. UFO in practice

The two terms refer to the same underlying category of observations. The choice between them is a question of register and historical accuracy, not of meaning.

The Council uses UAP for any case from 2019 onward — the year the Navy’s reporting category formally took effect — and for institutional and contemporary discussion of current policy, congressional action, and the AARO caseload. When discussing the 2021 ODNI assessment, the 2022 NDAA provisions, or any ongoing executive disclosure process, UAP is the correct term.

The Council uses UFO when the case predates the 2019 rebrand and the historical record uses that term: the 1947 Roswell incident, the 1952 Washington National sightings, the 1980 Rendlesham Forest event, the 1997 Phoenix Lights, or any pre-2019 mass-sighting case in which “UFO” is the term used by witnesses, investigators, and primary sources. Forcing UAP onto a 1947 newspaper headline introduces anachronism without analytical gain.

Cultural references retain the historical term. The “UFO community” exists; the “UAP community” does not, yet. When quoting cultural material, popular media, or popular-history sources, UFO is what is meant and is what we use.

The reverse is not symmetric. Using UFO to describe a 2024 Navy infrared video would be analytically wrong: the case enters the record under the UAP framework, is investigated by AARO under the UAP framework, and exists in the institutional system as a UAP file.

Council note on “anomalous”

The word “anomalous” in Unidentified Anomalous Phenomena does not mean alien. It does not mean non-human. It does not mean extraterrestrial. It means that the observed behavior, performance characteristics, or material properties of the object cannot be reconciled with the known capabilities of any catalogued human aircraft, spacecraft, watercraft, or conventional atmospheric or astronomical phenomenon.

That is a precise and limited claim. An object that decelerates from supersonic speed to a hover with no visible propulsion is anomalous. An object that descends into the ocean from altitude without producing a surface disturbance is anomalous. An infrared signature with no corresponding radar return, observed simultaneously by independent sensors, is anomalous.

What anomalous performance is not is automatically extraterrestrial. The same observation is consistent with — among other possibilities — a classified U.S. capability not catalogued in the analyst’s reference set, a foreign adversarial system using technology not yet attributed, a sensor artifact reproducible across multiple sensors, or a phenomenon of physics not yet understood. The Council’s verdict methodology requires that all such alternatives be considered before a case is treated as evidence of non-human intelligence. Most cases — including some of the most famous, such as the Tic Tac encounter — remain in Inconclusive status precisely because anomalous data is, on its own, not sufficient to warrant a stronger verdict.

This is the term as the Council uses it: precise, narrow, and disciplined. UAP is not a synonym for “alien.” It is a category of observed phenomena for which the conventional explanation has not been demonstrated.

AARO · UFO · NHI · ODNI · NUFORC · FLIR · AATIP · Tic Tac

Anchor cases: Tic Tac, USS Nimitz, 2004 · AARO FY2025 Report