Mausoleum, a magnificent sepulchral monument or tomb. From the tomb erected to Mausolus, by his wife Artemisia, at Halicarnassus, 379 B.C.

Metopes, literally faces, the square spaces between triglyphs in Doric architecture; occasionally applied to the sculptures fitted into these spaces.

Minaret, a slender lofty tower, a usual appendage of a Mohammedan mosque.

Monolith, of one stone.

Mortise, a hollow in a stone or timber to receive a corresponding projection.

Mosque, a Mohammedan place of worship.

Mutule, a feature in a Classic Doric cornice, somewhat resembling the end of a timber beam.

Narthex, in an early Christian church, the space next the entrance.

Obelisk, a tapering stone pillar, a feature of Egyptian architecture.

Opus Alexandrinum, the mosaic work used for floors in Byzantine and Romanesque churches.