Of a hillfort: defended by three or more concentric banks and ditches.
Muntin
The vertical part in the framing of a door, screen or (especially) panelling.
Murder hole
Small rectangular trap in the ceiling of an entrance passage in a castle or tower house.
Mutules
Square blocks attached to the underside of a Doric cornice, in line with the triglyphs.
Nailhead
Ornament in the Early English period of Gothic, consisting of small pyramids regularly repeated.
Naos
The space within a classical temple. Also called a cella.
Narthex
Enclosed vestibule or covered porch at the main entrance to a church.
Nave
The body of a church west of the crossing or chancel, often flanked by aisles.
Needle spire
A thin spire rising from the centre of a tower roof, well inside the parapet.
Neo-Baroque
Nottingham
The revival of the Baroque style, especially in early 20th-century Britain; also termed Edwardian Baroque. It tended to look back to English prototypes of the late 17th and early 18th centuries rather than to the more expansive models of the Continent, where Baroque architecture originated.