Nookshaft

Nookshaft - Shaft set in angle of jamb or pier.
Offset - Ledge marking the narrowing of a wall's thickness.
Oilette - A round opening at the base of a loophole, usually for a cannon muzzle ...

Nookshaft
Offset
ledge in a wall followed by reduced thickness of the wall ...

Necking - ornament at the top of a column, bottom of the capital.
Newel - center post of spiral staircase.
Niche - vertical recess in a wall, often to take a statue.
Nookshaft - shaft set in angle of jamb or pier.
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Contrast with: apse Nookshaft: Shaft set in angle of jamb or pier.
O Ogee or ogive arch: An arch with a pointed apex, formed by the intersection of two S curves usually confined to decoration and not used in arcade arches.

See also: Scaffolding, Pitch, Bond, Pillar, Church