Apollo 12 astronaut Alan Bean, wearing a helmet with visor, during the second moonwalk EVA near Sharp Crater.¹

A visor is a surface that protects the eyes, such as shading them from the sun or other bright light or protecting them from objects. Nowadays many visors are transparent, but before strong transparent substances such as polycarbonate were invented, visors were opaque like a mask with small holes to see and breathe through, such as:

• The part of a helmet in a suit of armor that protects the eyes.
• A type of hat consisting only of a visor and a way to fasten it to the head.
• Any such vertical surface on any hat or helmet.
• Any such horizontal surface on any hat or helmet (called a peak in British English).
• A device in an automobile that the driver or front passenger can lower over part of the windshield to block the sun (sun visor).

Some modern devices called visors are similar, for example:

• Visor (ice hockey)

Types of modern transparent visors include:

• The transparent or semi-transparent front part of a motorcycle crash helmet or police riotsquad helmets.
  • Safety faceshields for construction-type applications.²
• An eyeshield to protect the eyes from sunlight on an American football helmet.
• A shield to protect the eyes from sunlight on a flight helmet.
• Green eyeshades, formerly worn by accountants and others engaged in vision-intensive, detail-oriented occupations.

The word vizard (sometimes visard) is used in Shakespearean English to refer to a visor, a mask, or a disguise (ex. "There, then, that vizard, that superfluous case, that hid the worse and show'd the better face." -- Love's Labors Lost V.ii.387).

References

1. ^ Apollo 12 Image Library
2. ^ http://www.mcmaster.com/#catalog/114/1775