An etymology of unicorn in French

Rebracketing (also known as resegmentation or metanalysis) is a process in historical linguistics where a word originally derived from one set of morphemes is broken down or bracketed into a different set. For example, hamburger, originally from Hamburg+er, has been rebracketed into ham+burger, and burger was later reused as a productive morpheme in coinages such as cheeseburger. It is usually a form of folk etymology, or may seem to be the result of valid morphological processes. & https://en.wikipedia.org/wiki/Rebracketing