Backronym

A backronym is a name which appears to be an acronym, but is actually one where the short form was chosen first, and the long form (for which the former appears to be an acronym) was created/selected later.

The name of the text editor ZWEI ('ZWEI was EINE initially') is an example (although that one is also a recursive acronym); 'eine' and 'zwei' are German for 'one' and 'two'. A backronym for the programing language BASIC - 'Beginner's All-purpose Symbolic Instruction Code' - exists, also. Backronyms are often humorous; the backronym for the Nimrod routing architecture ('Nimrod: It Might Run One Day' - also a recursive acronym) - was created (by someone who worked on it) as a pointed joke about its chances for success. (They were unfortunately correct.)