Arcade: A series of arches supported by columns or piers.

Armatures: Iron framework used within mason-less Rose Windows to support the glass weight.

Barrel Vault: The simplest form of a vault, resembling a barrel, consisting of a continuous surface of semicircular or pointed sections.

Chevron: An ancient design motif used in Christian architecture dating back to the Romanesque period.

Cinquefoil: A five sided design of converging arcs.

Fan vaulting: A decorative and intricate form of tracery in which the ribs of a Vault arch out in a concave fan pattern.

Fillet: Delicate adornment strips applied to shafts and archways

Finial: An ornamental capping placed on the top of spires

Flying Buttress: The Flying Buttress was an innovative feature of Medieval Gothic architecture. The buttress was introduced when the weight of the ceilings would tend to buckle the walls outward and large piles of stone would be stacked along the wall in intervals to buttress (or support) the walls from pushing outward - these piles of stones became included in designs of structures, such as castles and cathedrals and were called buttresses.

Fluting: Carved grooves sculpted into piers, columns and pillars.

Gargoyles: In Architectural terms only the hideous carved creature serving as actual water spout is called a Gargoyle.

Grisaille: A stained glass window incorporating muted tones as opposed to bright colors.

Grotesques: A decorative sculpture known as a Grotesque. A grotesque may function solely as decoration not as a water spout as in a Gargoyle.

Hammer Beam: A short horizontal beam, usually made of wood, extending from the top of a masonry wall outward towards the center of an enclosed space, but not completely crossing it.

Keystone : The apex of the vault.

Niche: A recess in a wall.

Oriel: A projection from the upper story of a building often containing windows.  

Pinnacle: A vertical ornament forming the spire of a turret.

Rose Window: A circular window composed of patterned tracery arranged in petal-like, or Rose-like,, formation.

Spire: An elongated, pointed structure which rises from a tower, turret or roof.