Inherited from Old French vison, of uncertain origin. Perhaps borrowed from a Germanic source such as Frankish *wisulā (compare Old High German wisula (“weasel”). (An alternative suggestion that the term derives from Old High German wisunt (“bison”) is semantically implausible.)
Alternatively, perhaps from Vulgar Latin *viso, Latin visio (“to fart”), vissio (“stench”), in reference to their scent glands (near the anus).