A ''castellum'' in
Latin
Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, known as Latium. Through the power of the Roman Republic, it became ...

is usually:
*a small
Roman
Roman or Romans most often refers to:
*, the capital city of Italy
*, Roman civilization from 8th century BC to 5th century AD
*, the people of ancient Rome
*', shortened to ''Romans'', a letter in the New Testament of the Christian Bible
Roman ...
fortlet or tower,
[C. Julius Caesar, Gallic War; 2,30] a diminutive of ''
castrum
In the Roman Republic
The Roman Republic ( la, Rēs pūblica Rōmāna ) was a state of the ancient Rome, classical Roman civilization, run through res publica, public Representation (politics), representation of the Roman people. Beginning w ...

'' ("
military camp
A military camp or bivouac is a semi-permanent military base
A military base is a facility directly owned and operated by or for the military
A military, also known collectively as armed forces, is a heavily armed, highly organized forc ...

"), often used as a
watchtower
A watchtower is a type of fortification
A fortification is a military construction or building designed for the defense of territories in warfare, and is also used to establish rule in a region during peacetime. The term is derived from La ...

or signal station like on
Hadrian's Wall
Hadrian's Wall ( la, Vallum Aelium), also known as the Roman Wall, Picts' Wall, or ''Vallum Hadriani'' in Latin, is a former defensive fortification of the Roman province
The Roman provinces (Latin: ''provincia'', pl. ''provincia ...

. It should be distinguished from a ''
burgus
Artist's impression of the late Roman ''burgus'' of Asperden burgus, Goch-Asperden (D), core site with outer walls and ditch
A ''burgus'' (Latin, plural ''burgi '') or ''turris'' ("tower") is a small, tower-like Roman fort, fort of the Late A ...
'', which was a later Latin term that was used particularly in the
Germanic
Germanic may refer to:
* Germanic peoples, an ethno-linguistic group identified by their use of the Germanic languages
** List of ancient Germanic peoples and tribes
* Germanic languages
:* Proto-Germanic language, a reconstructed proto-language of ...

provinces.
*a distribution, header and settling tank in a
Roman aqueduct
The Ancient Rome, Romans constructed Aqueduct (bridge), aqueducts throughout their Roman Republic, Republic and later Roman Empire, Empire, to bring water from outside sources into cities and towns. Aqueduct water supplied Thermae, public baths, ...

or ''
it:castellum aquae''.
It is the source of the
English
English usually refers to:
* English language
English is a West Germanic languages, West Germanic language first spoken in History of Anglo-Saxon England, early medieval England, which has eventually become the World language, leading lan ...

word "
castle
A castle is a type of fortification, fortified structure built during the Middle Ages predominantly by the nobility or royalty and by Military order (monastic society), military orders. Scholars debate the scope of the word ''castle'', but u ...

".
References
Roman fortifications
Roman aqueducts
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