Ranks and Specialisms in the Roman Army
| Ab Epistulis | Secretary for Letters |
| Actarius | Accounts Clerk |
| Adiutor | Adjutant |
| Agrimensor | Surveyor |
| Aquilifer | Senior Standard Bearer |
| Architectus | Architect |
| Beneficiarius Consularis | Soldier exempt from menial duties, orderly on Governor's staff |
| Bucinatores | Trumpet Blowers |
| Capsarius | Medical Orderly |
| Cataphractus | Armoured Cavalryman |
| Centenarii | Centurion (early) |
| Cerarius | Clerk |
| Comes | Assistant |
| Cornicen | Horn Blower |
| Cornicularius | Tribune or Centurion’s secretary |
| Curator | Commander of unit containing Curator Veteranorum |
| Curator Veteranorum | Serving Legionary who has passed retirement age |
| Custos Armorum | Armourer |
| Draconarius | Standard Bearer |
| Dromedarius | Camel Rider |
| Duplicarius | Second in Command of Troop |
| Eques | Cavalry Trooper |
| Equites Cohortales | Cavalrymen in Infantry Cohort |
| Evocatus | Soldier recalled to, or retained with, the colours |
| Exactor | Tax Collector |
| Exactus | Clerk |
| Explorator | Scout |
| Excubitor | Sentinel |
| Excubitores Ad Signa | Soldiers on duty at the standards |
| Exercitator | Instructor |
| Fabricenses | Armourers |
| Frumentarius | Intelligence Officer |
| Hastilarius | Spear Thrower |
| Imaginifer | Standard Bearer carrying image of Emperor |
| Immunes | Men exempt from fatigues |
| Interpretes | Interpreters |
| Legatus Legionis | Commander of the Legion |
| Legionarius | Legionary |
| Librarius Caducorum | Clerk responsible for looking after belongings of those killed in battle |
| Librarius Depositorum | Savings Clerk |
| Librarius Horreorum | Granary records Clerk |
| Magister Campi | Drill Instructor |
| Medicus | Doctor |
| Mensor | Surveyor |
| Metatores | Surveyors |
| Miles | Private Soldier, Infantryman |
| Munifex | Private Soldier |
| Officium | The Governor’s Staff |
| Optio | Centurion’s understudy and Second in Command of Troop |
| Optio ad spem ordains | Man accepted for promotion to Centurionate, waiting for vacancy |
| Pecuarius | Animal keeper |
| Pedes | Foot Soldier |
| Praefectus | Prefect, Commander of an auxiliary, or allied unit |
| Praefectus Castrorum | Third in command of Legion, Camp Prefect |
| Praepositus | Commander of infantry or cavalry unit |
| Princeps | Officer responsible for training, and Headquarters staff, Senior Centurion |
| Principalis | Junior Officer (under Centurion) |
| Probatus | An officially enrolled Soldier |
| Publicanus | Tax Collector |
| Quaetionarius | Torturer or interrogator |
| Quaestor | Quartermaster |
| Sagittarius | Archer |
| Sesquiplicarius | Third in Command of Troop |
| Signifer | Standard Bearer |
| Speculatores | Spy, scout, or messenger |
| Strategus | Senior Officer |
| Strator | Groom |
| Tesserarius | Guard Commander |
| Tiro | Recruit |
| Tribunus | Senior Officer |
| Tribunus Angusticlavius | Junior Tribune |
| Tribunus Laticlavius | Senior Tribune |
| Tribunus Praepositus | Tribune in charge of detachment |
| Tribunus Stabuli | Tribune in charge of stables |
| Tubicen | Trumpeter |
| Velites | Lightly armed Legionaries |
| Venatores | Hunters |
| Veteranus | Veteran, a soldier who has re-enlisted |
| Vexillarius | Standard bearer who carried Vexillum (cloth flag) |
The above was compiled using information from Webster's "The Roman Imperial Army", Davies' "Service in the Roman Army", and Graham's "Dictionary of Roman Military Terms"
I've tried my best to make sure that the information is accurate, but if you do spot an error or you think something should be added please leave me a message. I can be e-mailed at: