O
OBSIDIO A seige
OCCIDEMTUM West (direction)
OCCIDENTALIS Western (location)
OCREAE / TIBIALE Greave, lower leg protection armor
OCTOBER Sacred to god of war "Mars", the eighth "Octavus" month of the 304 day, 10 month long "Romulus" Calendar, It became the tenth month of the 12 month "revised" Roman Republican Calendar in 200 BC / 552 AUC, Ab Urba Condita, "from the Founding of the City" (Rome), when February was moved between January and March / Martius and the Roman New Year was moved from March 1st (Kalends Martius) to January 1st (Kalends Januarius / Ianuarius). Consult "Roman Calendar" on our DateYearTime Page for a more details and explanation.
OFFICIUM The staff of a governor
ONAGER "Wildass" in Latin. The name for the classic one arm siege catapult used by the Romans. Its name came from the wild motions or "kick" and jump of the weapon after it was discharged. Also took its name from a pig kicking rocks behind itself when being chased. The Onager was much simpler and easier to construct than the more complicated Ballista, although it was not always as accurate.
OPERARIUS A Laborer / Unskilled Worker
OPIFEX A Skilled Laborer or Worker
OPPIDUM A fortified Celtic stronghold or town, usually on a hilltop
OPPUGNATIO An assault
OPTIME Very Well / Best
OPTIO Second in command of the Century or unit.
OPTIO AD SPEM ORDINIS An Optio accepted for promotion and waiting for a Centurion vacancy
OPTIO VALETUDINARII Officer in charge of a legionary hospital
ORDO A battle line, An early military unit division of a Legion
ORDO EQUESTER The Esquestrian Order to which most wealthy Roman citizens belonged; and from which members of the cavalry units and many senior officers and senators were drawn.
ORICHALCUM Roman Brass
ORIENTALIS East or Eastern
ORIGO Origin
OTIOSE Stand Easy (lit. in a leisurely manner)
OVATIO A triumphal entry reception given a victorius commander