The Roman Army: Legiō, Cohors and Castra
The structure of the Roman legion, the ranks of soldiers and the Latin words that survive in English military and place names.
The Roman army was one of history's most effective, and its vocabulary lives on in English.
The legion
The basic unit was the legiō (legion), made up of thousands of heavy infantry soldiers, called legiōnāriī. A legion was divided into smaller units:
| Latin | Meaning |
|---|---|
| legiō | legion, several thousand men |
| cohors | cohort, a tenth of a legion |
| centuria | century, about 80 men |
Ranks
| Latin | Meaning |
|---|---|
| mīles | soldier |
| centuriō | commander of a century |
| lēgātus | commander of a legion |
| imperātor | victorious general, later emperor |
The aquilifer carried the legion's aquila ("eagle"), its most important standard. Losing it was a disgrace.
Camp and campaign
A legion built a fortified camp, castra, every night when marching. The word survives in English place names ending in -chester, -caster and -cester, such as Manchester, Lancaster and Gloucester.
| Latin | Meaning |
|---|---|
| castra | camp |
| via | road |
| pōns | bridge |
| mūrus | wall |
| arma | weapons |
| gladius | short sword |
| scūtum | shield |
Roman roads and engineering
Soldiers built roads, bridges and forts as part of their service, and many modern roads follow Roman routes.
English words from the army
| English | Latin |
|---|---|
| military | mīlitāris |
| soldier | from solidus, a coin (soldiers were paid) |
| legion | legiō |
| castle | castellum, a small fort |
| arms, army | arma |
| victory | victōria |
| centurion | centuriō |
Famous phrases
- Vēnī, vīdī, vīcī. — I came, I saw, I conquered.
- Sī vīs pācem, parā bellum. — If you want peace, prepare for war.
Tips
- Learn legiō, cohors and centuria.
- Look for -chester in place names.
- Use the dictionary to check terms.
English Latin Dictionary
Offline English–Latin dictionary for students, classics and word-origin lookups
More about English Latin Dictionary
From Latin to Italian, Spanish, French and Portuguese
How everyday Latin turned into the Romance languages, with side-by-side word comparisons that help you spot patterns.
Read article →Great Latin Authors: Vergil, Ovid, Cicero and Caesar
A short tour of the major Roman writers, what each is famous for, and a famous opening line from each to practise reading.
Read article →Latin in Law: Habeas Corpus, Pro Bono and Prima Facie
The Latin terms still used in courts and legal writing, what each means literally, and how understanding the Latin helps you remember them.
Read article →Latin in Medicine and Science: From Anatomy to Prescriptions
How Latin shapes anatomy, medical terms and prescription abbreviations, with examples that show how to decode unfamiliar medical words.
Read article →