Templeborough Roman Fort in South Yorkshire visualised 3D flythrough, produced for Rotherham Museums and Archives.

In the Roman Republic and the Roman Empire, the Latin word castrum[1] (plural castra) was a building, or plot of land, used as a fortified military camp.

Castrum was the term used for different sizes of camps including a large legionary fortress, smaller auxiliary forts, temporary encampments, and "marching" forts. The diminutive form castellum was used for fortlets,[2] typically occupied by a detachment of a cohort or a century.

In English, the terms Roman fortress, Roman fort, and Roman camp are commonly used for castrum. However, scholastic convention tends toward the use of the words camp, marching camp, and fortress as a translation of castrum.[3]

For a list of known castra see List of castra.


Castrum appears in Oscan and Umbrian, two other Italic languages, suggests an origin at least as old as Proto-Italic language.

Julius Pokorny [4] traces a probable derivation from *k̂es-, schneiden (“cut”) in *k̂es-tro-m, Schneidewerkzeug (“cutting tool”).

These Italic reflexes based on *kastrom include Oscan castrous (genitive case) and Umbrian castruo, kastruvuf (accusative case). They have the same meaning, says Pokorny, as Latin fundus, an estate, or tract of land. This is not any land, but is a prepared or cultivated tract, such as a farm enclosed by a fence or a wooden or stone wall of some kind. Cornelius Nepos uses Latin castrum in that sense: when Alcibiades deserts to the Persians, Pharnabazus gives him an estate (castrum) worth 500 talents in tax revenues.[5] This is a change of meaning from the reflexes in other languages, which still mean some sort of knife, axe, or spear. Pokorny explains it as ’Lager’ als ‘abgeschnittenes Stück Land’, “a lager, as a cut-off piece of land.”

If this is the civilian interpretation, the military version must be “military reservation,” a piece of land cut off from the common land around it and modified for military use. All castra must be defended by works, often no more than a stockade, for which the soldiers carried stakes, and a ditch. The castra could be prepared under attack within a hollow square or behind a battle line. Considering that the earliest military shelters were tents made of hide or cloth, and all but the most permanent bases housed the men in tents placed in quadrangles and separated by numbered streets, one castrum may well have acquired the connotation of tent.[6]

Other Languages
العربية: كاسترا
български: Каструм
bosanski: Castrum
català: Castrum
čeština: Castrum
Cymraeg: Caer Rufeinig
español: Castrum
Esperanto: Castrum
euskara: Castrum
فارسی: کاستروم
français: Camp romain
hrvatski: Castrum
interlingua: Castrum
italiano: Castrum
עברית: קסטרום
magyar: Castrum
Nederlands: Castra
Nedersaksies: Castrum
日本語: カストラ
norsk: Castrum
română: Castru
русский: Каструм
slovenčina: Kastrum
slovenščina: Kastrum
српски / srpski: Каструм
srpskohrvatski / српскохрватски: Kastrum
suomi: Castra
svenska: Castrum
Türkçe: Castra
українська: Каструм