Definition of visor:
(n) :
a part of a
helmet, arranged so as to lift or open, and so show the face. The openings for seeing and breathing are generally in it; a mask used to disfigure or disguise
"1608, No visor does become black villainy So well as soft and tender flattery. — William Shakspeare, Pericles, Prince of Tyre, Act IV, Scene IV, line 44."