Merlons: See Battlements.
Metope: the space between any two of the Triglyphs (which see) of a Doric Frieze. Originally left open, later filled and often with sculptured relief.
Mezzanine: a low story situated between two higher ones.
Mihrab: a niche in the wall of a mosque that marks the “Kibleh,” or direction toward the Kaaba (which see) at Mecca.
Minaret: the tall slender tower, attached to a Mosque, from a balcony of which the muezzin summons the people to prayer.
Modillions: the decorated blocks ranged under the Cornice of a Corinthian or Composite Entablature.
Monolith (lit. single stone): usually of large size. Monolithic, composed of such.
Mosaic (lit. belonging to the muses, the goddesses of the arts): decorative designs composed of particles, usually cube-shaped, of marble, stone, glass or enamel, used to enrich the surfaces of vaults, walls and floors. See Opus.
Motive: in decoration, the form on which the ornament is based; e.g., the acanthus motive.
Mullion: one of the vertical stone bars dividing a Gothic window into two or more “lights.” Also one of the bars of a Rose-Window (which see). The horizontal bars are called Transoms.