machicolation: A gallery projecting on brackets and built on the outside of castle towers and walls,with openings in the floor through which to drop molten lead, boiling oil, and missiles.

Compare with hoarding

mandorla:An almond-shaped motif in which Christ sits; sometimes used also for the Virgin.

mask head: An animal head employed in conjunction with interlace or foliage motifs.

mausoleum: Structure for a tomb.

Compare with: sarcophagus, memorial brass
meander or Greek key: An ornamental motif consisting of continuous bands arranged in rectilinear forms.
See also other repetative decorative motifs

memorial brass: an engraved metal plate used as a commemorative monument. Sometimes these were set vertically, usually in a wall, but usually they were set horizonatlly, flush with the pavement of a church, to mark a tomb. The engraved areas were often filled with pigment.

Compare with mausoleum, sarcophagus

monstrance: Container for eucharistic wafers which contains an opening through which they can be viewed.

See also ciborium (definition 1), paten, pxy

mosaic: A decoration created by setting small pieces of glass, stone, or marble in a matrix- often concrete. Wall mosaics were most prevelent in the Early Christian and Byzantine periods, during which they were a very important form of wall decoration.

See also tessera

motte-and-bailey: A defensive system consisting of a mound of earth (the motte) with a wooden tower on top, placed within a courtyard (the bailey, also called the ward).

Compare with keep

mullion: The vertical element that separates the lancets of a window.

Compare with lancet