noun

• (poetic) Appearance, likeness.
  "Come then, pure hands, and bear the head ⁠That sleeps or wears the mask of sleep, ⁠And come, whatever loves to weep, And hear the ritual of the dead."
• (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.
• (fortification) In a permanent fortification, a redoubt which protects the caponiere.

verb

• (transitive) To cover (the face or something else), in order to conceal the identity or protect against injury; to cover with a mask or visor.
  "They must all be masked and vizarded"
• (transitive) To disguise as something else.
• (transitive) To conceal from view or knowledge; to cover; to hide.
  "Masking the business from the common eye"
• (transitive, military) To conceal; also, to intervene in the line of.

noun

• (UK dialectal, Scotland) The mesh of a net; a net; net-bag.

noun

• (UK dialectal) Mash.