A Mask

A cover, or partial cover, for the face, used for disguise or protection.
That which disguises; a pretext or subterfuge.
A festive entertainment of dancing or other diversions, where all wear masks; a masquerade.
A person wearing a mask.
(obsolete) A dramatic performance in which the actors wore masks and represented mythical or allegorical characters.
(architecture) A grotesque head or face, used to adorn keystones and other prominent parts, to spout water in fountains, and the like.Synonym: mascaron
(fortification) In a permanent fortification, a redoubt which protects the caponiere.
(fortification) A screen for a battery.
(zoology) The lower lip of the larva of a dragonfly, modified so as to form a prehensile organ.
(publishing, film) A flat covering used to block off an unwanted portion of a scene or image.
(computing, programming) A pattern of bits used in bitwise operations; bitmask.
(computer graphics) A two-color (black and white) bitmap generated from an image, used to create transparency in the image.
(heraldry) The head of a fox, shown face-on and cut off immediately behind the ears.
(psychology) A social phenomenon where autistic people learn, practice, and perform certain behaviors and suppress others in order to appear more neurotypical.