Clone troopers belonging to a regiment on Geonosis
A large ground infantry unit was called a regiment. Within the Grand Army of the Galactic Republic, each corps was composed of sixteen regiments. These regiments consisted of 2,304 clone troopers, each under the command of a Clone Commander. Furthermore, each regiment was divided into sixteen companies. A single regiment of the Republic was structured with four battalions, and those battalions were further divided into four companies each. During the events of the First Battle of Geonosis, Yoda's regiment was instrumental in rescuing Senator Padmé Amidala and the Jedi from the dangers of the Petranaki Arena. The Confederacy of Independent Systems also utilized regiments in its Droid Army, with several regiments forming part of the Hissrich droid unit.
Within the ranks of the Stormtrooper Corps, a regiment was made up of four battalions, resulting in a total of 3,200 stormtroopers. A legion was comprised of four Imperial regiments. General Crix Madine of the Rebel forces noted that Imperial regiments were particularly known for their unwavering obedience. Imperial Army troopers could also be organized into a regiment.