Ave: Salute used by the Roman army. Latin for “Hail”

Legio/Legion: Largest tactical unit in the Roman army
consisting of over 5000 men. Commanded by a Legate.

Cohort: Second largest tactical unit in the Roman army
consisting of 480 men. 10 per legion. Commanded by a Senior Centurion.

Centuria: Third largest tactical unit in the Roman army
consisting of 80 men. 6 per Cohort. Commanded by a Centurion.

Contubernium: Smallest unit in the Roman army consisting of
8 men. 10 per Centuria. Commanded by a Decanus.

Siege ballista: A type crossbow-like of siege weapon powered
by torsion springs. Ranging in sizes a from hand held weapon to the size of a
large house.

Scorpio ballista: A small crossbow-like sniper weapon
powered by torsion springs, manned by two men.

Decanus: a non-commissioned officer that commanded a contubernium.

Contubernium:
contubernium means “tent group” in Latin and was the smallest unit in the roman
military containing eight to ten men. This unit was commanded by a Decanus.

Legate: The
commander of a legion. Usually appointed by the Emperor. 

Testudo Formation: Known as the tortoise formation in
English, This combat formation was used provide missile protection so as to get
close to a fortified location.

Torsion spring: A spring that creates tension by twisting
rope or wire. Used to power all Roman siege weapons.

Charcloth: a swatch of fabric made from vegetable fiber
Charcloth ignites with even the smallest spark, and is therefore commonly used
with a flint and steel.

Gladius: Short stabbing sword used by all Roman infantry.

Praetorian Guard: Rome’s most elite. Acted as the guard of the emperor, somewhat similar to the secret service.

Auxilia: Specialized troops recruited from various tribes under the empire. The Auxilia consisted mostly of light infantry to support the Legionary units, archers, and cavalry.