UAP is an abbreviation of unidentified aerial phenomenon (or phenomena), a term that refers to things observed in the sky that cannot be identified as aircraft or other known phenomena.

UAP is often used in the same way as the more popular term UFO (which stands for unidentified flying object), including sometimes being pluralized as UAPs when referring to multiple things that have been observed.

However, use of UAP instead of UFO, including in official ways by US government agencies, is sometimes seen as a way of avoiding popular connotations associated with the term UFO, including the implication that they are alien spacecraft.

Still, UAP and UFO are often used interchangeably, and UAP is used by some who believe that some phenomena that have been observed are in fact extraterrestrial in origin.

In 2020, the US Department of Defense (DoD) approved the creation of the Unidentified Aerial Phenomena Task Force to catalog and study UAP, leading to increased use of the term, especially in media reports on the topic. Interest around the term rose again in the summer of 2021 with the release of a report by the task force.

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