1911 Encyclopædia Britannica/Visor

VISOR (also spelled viser, vizor, vizard or visard), a term now used generally of the various forms of movable face-guards in the helmet of medieval and later times. It meant properly a mask for the face, and is an adaptation of the O.Fr. visiere, mod. visière, as is seen by the M.E. forms viser, visere. It is thus to be referred to the Fr. vis, face, Lat. visus, from videre, to see. In this sense the word “visor” is modern, the movable guard for the upper part of the face being known as an “aventail” or “ventail,” and that for the lower part a “beaver” (see Helmet).