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40+ Fort and Castle Architecture Terms A–Z (With Pictures)

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The author has a great appreciation of art history and the architecture of the Middle Ages.

Bled Castle, a medieval castle in Bled, Slovenia

Bled Castle, a medieval castle in Bled, Slovenia

Medieval Castle Architecture and Design Terminology A–Z

The Middle Ages, or the medieval period, was a fascinating period in human history filled with wonderous events: the fall of the Roman Empire, the founding of the first universities, numerous technological and cultural transformations, and the Black Death.

The architecture of the medieval period was marked by several distinctive styles, including Gothic, Renaissance, and French. Castles and forts were built for protection and were the primary secular architecture of the Middle Ages. In this article, you'll find an A–Z list of the most common terms used in medieval castle and fort architecture, along with photos.


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.

No evidence indicates 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 storerooms.


An arrowslit (often 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.


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.


The banquette refers to a continuous step built into the interior of the parapet, enabling the defenders to shoot over the top with small arms.


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 that 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.


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.

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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.


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.

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.



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.

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 citadel is 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.

Curtain Wall

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

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

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


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.


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 torture probably belongs more to the Renaissance period.

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

Embrasures at Mdina, Malta

Embrasures at Mdina, Malta


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.


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, towers, and walls.

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.


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.

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.


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 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 Towers or Clarence Towers of Warwick Castle

Gate Towers or Clarence Towers of Warwick Castle

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.



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.


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.