For the past 70 years most people who needed to describe a mysterious thing in the sky would use the word UFO, an abbreviation of unidentified flying object. In recent years some organizations and people have started replacing UFO with UAP, i.e. “unidentified aerial phenomena.”
”A spate of shootdowns involving balloons and other flying objects over North America comes as the US military is becoming more sensitive to unidentified aerial phenomena.”
— New Scientist, 13 Feb. 2023
A major reason why people might prefer UAP to UFO is that UFO is what language observers call “skunked.” This happens when a word’s use becomes problematic, either because it is likely to offend, or because it has lost its clarity of meaning. UFO is skunked because even though its literal meaning is neutral (“unidentified flying object” means almost exactly the same thing as “unidentified aerial phenomenon”), people tend to equate UFOs with alien spacecraft, Martian invaders, etc.
Aside from UAP’s more encompassing description, this term avoids the heavy cultural baggage attached to UFO, whose initial association with extraterrestrial origins, however true or untrue it may prove upon final analysis, sets up a narrow and inflexible framework for honest scientific research.
— Mark A. Raimer, Et Cetera, Spring 1999
The skunking of UFO is an unusual case. Most words that fall out of favor and get replaced by synonyms have been viewed as insensitive or offensive. These might include, for example, the shift from “old-age home” to “assisted-living facility.”
UFO has been skunked not because it offends, but because it now seems a little… goofy. How many other words have fallen out of favor for similar reasons? Few come to mind, although one might be “ping pong,” which serious players are more likely to call “table tennis.”
The term UAP first appeared in the late 1960s, while unidentified flying object has been around since 1947. (UAP sometimes refers to “unidentified autonomous phenomenon,” which has a similar meaning.)
It's too soon to say whether this new word will replace UFO entirely, but either way, we at Merriam-Webster will continue watching the language—and the skies—for UAP.
Update: This word was added in September 2023.
