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Basics / Updated 2026-09-30 / 2 min read

UFO vs UAP: Meaning, Differences and Official Usage

UFO means unidentified flying object. UAP now means unidentified anomalous phenomena in U.S. official usage. Neither label establishes an object's origin.

Reviewed and maintained byGlobal UFO Archive Editorial DeskEditorial policy

Quick answer

UFO expands to unidentified flying object; UAP expands to unidentified anomalous phenomena in current U.S. official usage. Older documents also use UAP for unidentified aerial phenomena. The newer wording broadens the description beyond a flying object, but changing the label does not add evidence or establish alien technology.

Official sources used

Key points

  1. UFO describes an unidentified flying object; UAP can describe a phenomenon or detection without first identifying a craft.
  2. Read the expansion used by the source: aerial and anomalous share the same acronym.
  3. Neither word is a conclusion about extraterrestrial origin.
Terminology diagram comparing the historical term UFO with the broader official term UAP
UFOUAP.net editorial diagram based on AARO, NASA and ODNI material; this is an explanatory graphic, not event evidence. UFOUAP.net editorial diagram based on AARO, NASA and ODNI material

What does UFO mean?

UFO is the English abbreviation for unidentified flying object. NARA retains that wording in historical collections such as Project Blue Book, so it remains useful when locating older records. The term describes a lack of identification in the report being discussed. It does not, by itself, distinguish a spacecraft from an aircraft, a light, an astronomical object or an observation that cannot now be reconstructed.

Sources: UFO and UAP records: textual and microfilm

Why does UAP have two expansions?

Unidentified aerial phenomena appears in older official material, including the 2020 Navy-video statement. NASA now uses unidentified anomalous phenomena and explains that this follows the terminology of the National Defense Authorization Act. NASA also notes that its independent study mainly concerned aerial phenomena. When quoting a historical document, preserve its original wording and date rather than silently changing aerial to anomalous.

Sources: UAP FAQs: terminology, evidence and the 2023 study · Statement on the release of historical Navy videos, 27 April 2020

A label is not a finding about origin

Read beyond the acronym to the evidence: what was observed, what was measured and what remains unavailable? A witness description, a recorded image and an analyst's conclusion are different kinds of information. NASA emphasizes that many observations lack enough data for scientific conclusions. Renaming a UFO report as a UAP report does not resolve those gaps. Nor does it make the witness dishonest when an ordinary explanation is later established.

Sources: UAP FAQs: terminology, evidence and the 2023 study · Identifying UFOs and UAPs

FAQ

Is UAP just another name for UFO?

They overlap, but UAP uses phenomena rather than flying object and current U.S. usage says anomalous. Check how the source defines the term.

Does UAP mean unidentified aerial or anomalous phenomena?

Both expansions occur in official records. NASA currently uses unidentified anomalous phenomena; older records may say unidentified aerial phenomena.

Does either term mean an alien spacecraft?

No. Neither acronym is evidence of extraterrestrial origin. Identification and origin require evidence beyond the label.

Sources

Documents