Backronym
In doing a bit of research for Holy Crap! Facts about whether or not the word "tip" was actually an acronym for "to insure ...
This was first posted on anonymous's blog. VISIT THE ORIGINAL
In doing a bit of research for Holy Crap! Facts about whether or not the word “tip” was actually an acronym for “to insure promptness” (it is not), I ran across the word backronym. The word is defined on Wikipedia as “a phrase that is constructed ‘after the fact’ from a previously existing word or abbreviation, the abbreviation being an initialism or an acronym.” I thought that was pretty cool. Wikipedia also has a short list of backronyms.