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bacronym, backronym (s) (noun)
; bacronyms, backronyms (pl)
Taking a word which already exists and creating a phrase, usually humorous, using the letters of the word as initials; and so the process is the opposite of producing an acronym.
Here is an example of a bacronym: SURFSIDE: Small Unified Reactor Facility with Systems for Isotopes, Desalting, and Electricity.
Another example of a bacronym: BANANA or "Build Absolutely Nothing Anywhere Near Anybody"; and GOD or "Guaranteed Overnight Delivery".