In a online dictionary says that "mask" comes from the medieval French "masque" and before maybe from Arabic maskhara "buffoon" and that from sakhira "to ridicule" but there's another possible origin from Provencal or Occitan "mascarar" or Old French "mascurer" "to darken the face", "to make black something". here: http://www.etymonline.com/index.php?search=mask&searchmode=none