Definition of mask

• n. - A cover, or partial cover, for the face, used for disguise or protection; as, a dancer's mask; a fencer's mask; a ball player's mask.
• n. - That which disguises; a pretext or subterfuge.
• n. - A festive entertainment of dancing or other diversions, where all wear masks; a masquerade; hence, a revel; a frolic; a delusive show.
• n. - A dramatic performance, formerly in vogue, in which the actors wore masks and represented mythical or allegorical characters.
• n. - A grotesque head or face, used to adorn keystones and other prominent parts, to spout water in fountains, and the like; -- called also mascaron.
• n. - In a permanent fortification, a redoubt which protects the caponiere.
• n. - A screen for a battery.
• n. - The lower lip of the larva of a dragon fly, modified so as to form a prehensile organ.
• v. t. - To cover, as the face, by way of concealment or defense against injury; to conceal with a mask or visor.
• v. t. - To disguise; to cover; to hide.
• v. t. - To conceal; also, to intervene in the line of.
• v. t. - To cover or keep in check; as, to mask a body of troops or a fortess by a superior force, while some hostile evolution is being carried out.
• v. i. - To take part as a masker in a masquerade.
• v. i. - To wear a mask; to be disguised in any way.