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Terminologies in Castles and forts architecture



Fortifications are military constructions or buildings designed for the defense of territories in warfare and also used to solidify rule in a region during peacetime. Humans have constructed defensive works for many thousands of years, in a variety of increasingly complex designs.


A gatehouse, in architectural terminology, is a building enclosing or accompanying a gateway to a castle, manor house, fort, town or similar buildings of importance. There are numerous surviving examples in France, Austria, and Germany.


Gate tower

A gate tower is a tower built over or next to a major gateway.

Usually, it is part of a medieval fortification. The gate tower may be built as a twin tower on either side of an entranceway. Even in the design of modern building complexes, gate towers may be constructed symbolically as the main entrance.

Gate Towers or Clarence Towers of Warwick Castle

Gate Towers or Clarence Towers of Warwick Castle

Bent entrance

A bent entrance is a defensive feature in medieval fortification. In a castle with a bent entrance, the gate passage is narrow and turns sharply. Its purpose is to slow down attackers attempting to rush the gate and impede the use of battering rams against doors.

Flanking tower

A flanking tower is a fortified tower that is sited on the outside of a defensive wall or other fortified structure and thus forms a flank. From the defensive platform and embrasures the section of wall between them (the curtain wall) could be swept from the side by ranged weapons.

Fortified tower

A fortified tower (also defensive tower or castle tower or, in context, just tower) is one of the defensive structures used in fortifications, such as castles, along with curtain walls. Castle towers can have a variety of different shapes and fulfill different functions.


The roundel is a strong artillery fortification with a rounded or circular plan of a similar height to the adjacent defensive walls. If the fortification is clearly higher than the walls it is called a battery tower.


A dungeon is a room or cell in which prisoners are held, especially underground. Dungeons are generally associated with medieval castles, though their association with tortureprobably belongs more to the Renaissance period.

An oubliette or bottle dungeon is a form of dungeon which is accessible only from a hatch or hole (an angstloch) in a high ceiling.


An angstloch is usually located above the basement of a fighting tower or bergfried. The description of these basement rooms as "dungeons" stems from the castle studies of the 19th century. There is no evidence to indicate that prisoners were really lowered through the angstloch into the dungeon using a rope or rope ladder as these 19th century accounts suggest. Archaeological finds, by contrast, indicate the use of these basement spaces as store rooms.


A bastion is a structure projecting outward from the curtain wall of a fortification, most commonly angular in shape and positioned at the corners. The fully developed bastion consists of two faces and two flanks with fire from the flanks being able to protect the curtain wall and also the adjacent bastions.


An arrowslit (often also referred to as an arrow loop, loophole or loop hole, and sometimes a balistraria) is a narrow vertical aperture in a fortification through which an archer can launch arrows.


Enceinte (from Latin incinctus: girdled, surrounded) is a French term denoting the "main defensive enclosure of a fortification". For a castle, this is the main defensive line of wall towers and curtain walls enclosing the position. For a settlement, it would be the main town wall with its associated gatehouses and towers and walls.

Curtain wall

A curtain wall is a defensive wall between two towers (bastions) of a castle, fortress.


Pillboxes are concrete dug-in guard posts, normally equipped with loopholes through which to fire weapons. The originally jocular name arose from their perceived similarity to the cylindrical and hexagonal boxes in which medical pills were once sold.

Pillbox stepped embrasure, Taunton Stop Line, England

Pillbox stepped embrasure, Taunton Stop Line, England


A bartizan also called a guerite or échauguette, or spelled bartisan, is an overhanging, wall-mounted turret projecting from the walls of late medieval and early-modern fortifications from the early 14th century up to the 18th century. Most frequently found at corners, they protected a warder and enabled him to see his surroundings. Bartizans generally are furnished with oillets or arrow slits.The turret was usually supported by stepped masonry corbels and could be round or square.


In military architecture, an embrasure is the opening in a crenellation or battlement between the two raised solid portions or merlons, sometimes called a crenel or crenelle.In domestic architecture, this refers to the outward splay of a window or arrow slit on the inside.

Embrasures at Mdina, Malta

Embrasures at Mdina, Malta


A merlon is the solid upright section of a battlement (a crenelated parapet) in medieval architecture or fortifications. Merlons are sometimes pierced by narrow, vertical embrasures or slits designed for observation and fire. The space between two merlons is called a crenel, and a succession of merlons and crenels is a crenellation.Crenels designed in later eras for use by cannons were also called embrasures.

merlons from Dinefwr Castle

merlons from Dinefwr Castle


A ravelin is a triangular fortification or detached outwork, located in front of the inner works of a fortress (the curtain walls and bastions). Originally called a demi-lune, after the lunette, the ravelin is placed outside a castle and opposite a fortification curtain.



In architecture, a turret (from Italian: torretta, little tower; Latin: turris, tower) is a small tower that projects vertically from the wall of a building such as a medieval castle. Turrets were used to provide a projecting defensive position allowing covering fire to the adjacent wall in the days of military fortification.



A palisade—sometimes called a stakewall or a paling—is typically a fence or wall made from wooden stakes or tree trunks and used as a defensive structure or enclosure.


A keep (from the Middle English kype) is a type of fortified tower built within castles during the Middle Ages by European nobility. Scholars have debated the scope of the word keep, but usually consider it to refer to large towers in castles that were fortified residences, used as a refuge of last resort should the rest of the castle fall to an adversary.


A moat is a deep, broad ditch, either dry or filled with water, that is dug and surrounds a castle, fortification, building or town, historically to provide it with a preliminary line of defence.

'Caerlaverock Castle

'Caerlaverock Castle


In fortification architecture, a rampart is a length of bank or wall forming part of the defensive boundary of a castle, hillfort, settlement or other fortified site. It is usually broad-topped and made of excavated earth or masonry or a combination of the two.

The rampart of the Cité de Carcassonne in the Aude department of France.

The rampart of the Cité de Carcassonne in the Aude department of France.


A yett (from the Old English and Scots language word for "gate")is a gate or grille of latticed wrought iron bars used for defensive purposes in castles and tower houses.Unlike a portcullis, which is raised and lowered vertically using mechanical means, yetts are hinged in the manner of a traditional gate or door and secured by bolts attached to the yett, or by long bars drawn out from the wall or gateway.


Sally port

A sally port is a secure, controlled entryway to a fortification or prison. The entrance is usually protected by some means, such as a fixed wall on the outside, parallel to the door—which must be circumvented to enter and prevents direct enemy fire from a distance. It may include two sets of doors that can be barred independently to further delay enemy penetration.


A mantrap, air lock, sally port or access control vestibule is a physical security access control system comprising a small space with two sets of interlocking doors, such that the first set of doors must close before the second set opens.


Garderobe is a historic term for a room in a medieval castle. The Oxford English Dictionary gives as its first meaning a store-room for valuables, but also acknowledges "by extension, a private room, a bed-chamber; also a privy". Its most common use now is as a term for a castle toilet.


A portcullis (from the French porte coulissante, "sliding door") is a heavy vertically-closing gate typically found in medieval fortifications, consisting of a latticed grille made of wood, metal, or a combination of the two, which slides down grooves inset within each jamb of the gateway.

Portcullis at Cahir Castle

Portcullis at Cahir Castle


A drawbridge or draw-bridge is a type of movable bridge typically associated with the entrance of a castle and a number of towers, surrounded by a moat. In some forms of English, including American English, the word drawbridge commonly refers to all types of movable bridges, such as bascule bridges, vertical-lift bridges, and swing bridges, but this article concerns the narrower, more historical definition of the term.

Drawbridge at the fort of Ponta da Bandeira; Lagos, Portugal

Drawbridge at the fort of Ponta da Bandeira; Lagos, Portugal


A Motte-and-bailey castle is a fortification with a wooden or stone keep situated on a raised earthwork called a motte, accompanied by an enclosed courtyard, or bailey, surrounded by a protective ditch and palisade.


In fortifications, a bailey or ward refers to a courtyard enclosed by a curtain wall. In particular, an early type of European castle was known as a Motte-and-bailey. Castles can have more than one bailey. Their layout depends both on the local topography and the level of fortification technology employed, ranging from simple enclosures to elaborate concentric defenses. In addition to the gradual evolution of more complex castle plans, there are also significant differences in regional traditions of military architecture regarding the subdivision into baileys.The bailey was a very useful fortification and many castles used it.


A fortress, typically one on high ground above a city. It may be a fortress, castle, or fortified center. The term is a diminutive of "city" and thus means "little city", so called because it is a smaller part of the city of which it is the defensive core. Ancient Sparta had a citadel as did many other Greek cities and towns.

Siege tower

A siege tower or breaching tower (or in the Middle Ages, a belfry) is a specialized siege engine, constructed to protect assailants and ladders while approaching the defensive walls of a fortification. The tower was often rectangular with four wheels with its height roughly equal to that of the wall or sometimes higher to allow archers to stand on top of the tower and shoot arrows into the fortification. Because the towers were wooden and thus flammable, they had to have some non-flammable covering of iron or fresh animal skins.


A machicolation is a floor opening between the supporting corbels of a battlement, through which stones or other material, such as boiling water or boiling cooking oil, could be dropped on attackers at the base of a defensive wall. A smaller version found on smaller structures is called a box-machicolation.

Chemin de ronde

In early fortifications, high castle walls were difficult to defend from the ground. The chemin de ronde was devised as a walkway allowing defenders to patrol the tops of ramparts, protected from the outside by the battlements or a parapet, placing them in an advantageous position for shooting or dropping.


A barbican is a fortified outpost or gateway, such as an outer defense to a city or castle, or any tower situated over a gate or bridge which was used for defensive purposes. Usually, barbicans were situated outside the main line of defenses and connected to the city walls with a walled road called the neck.

Murder hole

A murder hole or meurtrière is a hole in the ceiling of a gateway or passageway in a fortification through which the defenders could fire, throw or pour harmful substances or objects, such as rocks, arrows, scalding water, hot sand, quicklime, tar, or boiling oil, down on attackers.


A battlement in defensive architecture, such as that of city walls or castles, comprises a parapet (i.e., a defensive low wall between chest-height and head-height), in which gaps or indentations, which are often rectangular, occur at intervals to allow for the launch of arrows or other projectiles from within the defenses. These gaps are termed "crenels" (also known as carnels, embrasures, or wheelers), and the act of adding crenels to a previously unbroken parapet is termed crenellation.


A continuous step built into the interior of the parapet, enabling the defenders to shoot over the top with small arms.


In medieval fortresses, a bretèche or brattice is a small balcony with machicolations, usually built over a gate and sometimes in the corners of the fortress' wall, with the purpose of enabling defenders to shoot or throw objects at the attackers huddled under the wall. Depending on whether they have a roof, bretèches are classified into two types: open and closed. The open ones were accessed from the battlement's wall walk, or from a crenel.



The top surface or "fighting platform" of the rampart, behind the parapet.


The Zwinger of a castle is sited in front of the main curtain wall and is enclosed on the outer side by a second, lower wall, known as the Zwinger wall (Zwingermauer). If attackers succeed in getting past the Zwinger wall, they would be trapped in the Zwinger and were an easy target for the defenders on the main wall (Hauptmauer). Further progress was thus seriously impeded.



A hoard or hoarding (also known as a brattice or brettice, from the French bretèche) was a temporary wooden shed-like construction that was placed on the exterior of the ramparts of a castle during a siege to allow the defenders to improve their field of fire along the length of a wall and, most particularly, directly downwards to the wall base. The latter function was capably taken up by the invention of machicolations, which were an improvement on hoardings, not least because masonry does not need to be fire-proofed. Machicolations are also permanent and siege-ready.



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This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.


Alison on January 08, 2020:

Amazing article! Highly informative...Thanks for sharing

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