backronym

English

Examples
BASIC (“Beginner's All-purpose Symbolic Instruction Code”) MADD (“Mothers Against Drunk Driving”) POSH (“Port Out, Starboard Home”) (folk etymology) SAD (“Seasonal Affective Disorder”) USA PATRIOT Act WASH (“Water, Sanitation and Hygiene”)

backronym (plural backronyms)

A word that is originally not an acronym but is turned into one by devising a full form for it, sometimes as a folk etymology, sometimes as a contrived acronym to name a new organization, proposal, or other entity.
- 2018 March 14, Sarah Lewin, “Meet ‘Steve,’ the Aurora-Like Mystery Scientists Are Beginning to Unravel”, in space.com, retrieved 17 March 2018:
  he phenomenon has been dubbed STEVE, a backronym that matches the name originally given by aurora watchers. (STEVE is short for "Strong Thermal Emission Velocity Enhancement.")
- 2022 November 12, Matteo Wong, “How Did America End Up With the Z.O.M.B.I.E. Act?”, in The Atlantic‎:
  These reverse-engineered acronyms, or “backronyms,” are inescapable on Capitol Hill. Two of the biggest laws of the past few years were the CARES Act, for pandemic relief, and the CHIPS for America Act, for semiconductor manufacturing.

word that is originally not an acronym but is turned into one by devising a full form for it

backronym (third-person singular simple present backronyms, present participle backronyming or backronymming, simple past and past participle backronymed or backronymmed)