3. A festive entertainment of dancing or other diversions, where all
wear masks; a masquerade; hence, a revel; a frolic; a delusive show.
Bacon.
This thought might lead me through the world's vain mask.
Milton.
4. A dramatic performance, formerly in vogue, in which the actors wore
masks and represented mythical or allegorical characters.
5. (Arch.) A grotesque head or face, used to adorn keystones and other
prominent parts, to spout water in fountains, and the like; -- called
also mascaron.
6. (Fort.) (a) In a permanent fortification, a redoubt which protects
the caponiere. (b) A screen for a battery.
7. (Zoöl.) The lower lip of the larva of a dragon fly, modified so as
to form a prehensile organ.