Allure or Wall-walk: passage behind the parapet of a castle wall

Apse: circular or polygonal end of a tower or chapel

Arcading: rows of arches supported on columns, free-standing or attached to a wall (blind arcade)

Arrow Loop: A narrow vertical slit cut into a wall through which arrows could be fired from inside

Ashlar: blocks of smooth, squared stone of any kind

Bailey or Ward: courtyard within the walls of the castle

Ballista: engine resembling a crossbow, used in hurling missiles or large arrows

Barbican: an outwork or forward extension of a castle gateway

Barrel vault: semicircular roof of stone & timber

Bartizan: overhanging corner turret

Bastion: a small tower at the end of a curtain wall or in the middle of the outside wall

Battlement: a narrow wall built along the outer edge of the wall walk to protect soldiers against attack

Belfry: tall, movable wooden tower on wheels, used in sieges

Brattice: (see hoarding)

Buttery: room for the service of beverages

Concentric: having two sets of walls, one inside the other

Crenelation: a notched battlement made up of alternate crenels (openings) and merlons (square sawteeth)

Cross-wall: an internal dividing wall in a great tower

Curtain wall: a castle wall enclosing a courtyard

Cut: assault tower

Corbel: stone bracket projecting from a wall or corner to support a beam

Donjon: the inner stronghold (keep) of a castle

Drawbridge: a wooden bridge leading to a gateway, capable of being raised or lowered

Drum Tower: a round tower built into a wall

Dungeon: the jail, usually found in one of the towers

Enceinte: an enclosing wall, usually exterior, of a fortified place

Embrasure: the low segment of the altering high and low segments of a battlement

Escalade: scaling of a castle wall

Finial: a slender piece of stone used to decorate the tops of the merlons

Forebuilding: a projection in front of a keep or donjon, containing the stairs to the main entrance

Garderobe: latrine

Gate House: the complex of towers, bridges, and barriers built to protect each entrance through a castle or town wall

Hall: principle living quarters of a medieval castle or house

Hoarding: covered wooden gallery affixed to the top of the outside of a tower or curtain to defend the castle

Inner Ward or Inner Bailey: open area in the center of a castle

Keep: the inner stronghold of the castle

Loophole: slit in wall for light, air, or shooting through

Machicolation: a projection in the battlements of a wall with openings through which missiles could be dropped on besiegers

Mangonel: stone throwing machine worked by torsion, used as a siege weapon against castles

Merlon: part of a battlement, the square "sawtooth" between crenels

Meurtriere: arrow loop, slit in battlement or wall to permit firing of arrows or for observation

Moat: a deep trench usually filled with water that surrounded a castle

Motte: an earthwork mound on which a castle was built

Murder Holes: a section between the main gate and a inner portcullis where arrows, rocks, and hot oil could be dropped from the roof though holes

Oilette: a round opening at the base of a loophole

Oriel or Oriel Window: projecting room on an upper floor, later an upper-floor bay window

Oubliette: a dungeon reached by a trap door

Palisade: a sturdy wooden fence built to enclose a site until a permanent stone wall could be constructed

Parapet: protective wall at the top of a fortification, around the outer side of the wall:walk

Portcullis: vertical sliding wooden grille shod with iron suspended in front of a gateway, let down to protect the gate

Postern Gate: secondary gate or door

Putlog Hole: a hole intentionally left in the surface of a wall for insertion of a horizontal pole

Ram: battering ram

Revet: face with a layer of stone, stone slabs etc., for more strength. Some earth mottes were revetted with stone.

Sapping: undermining, as of a castle wall

Screens: wooden partition at the kitchen end of a hall, protecting a passage leading to the buttery, pantry, and kitchen

Solar: originally a room above ground level, but commonly applied to the great chamber or a private sitting room off the great hall

Springald: war engine of the catapult type, employing tension

Trebuchet: war engine developed in the Middle Ages employing counterpoise

Turning Bridge: a drawbridge that pivoted in the middle

Turret: a small tower rising above and resting on one of the main towers, usually used as a look out point

Wall Walk: the area along the tops of the walls from which soldiers could defend the castle

Ward: courtyard or bailey