The 332nd Company clone troopers are seen here on the Tribunal.
A company was a type of infantry formation used on the ground. Within the Grand Army of the Galactic Republic, a regiment contained sixteen companies, each comprised of 144 clone troopers and commanded by a Clone Captain. These companies were further broken down into four platoons. Conversely, in the Stormtrooper Corps, a company was made up of four platoons, for a total of 200 stormtroopers. Four Imperial companies would then form a battalion.
During the Clone Wars, Captain Rex, a clone, led both the 501st Legion's Torrent Company and the 332nd Company. Other companies in the Grand Army included Ghost Company of the 212th Attack Battalion, Green Company from the 41st Elite Corps, and Tango Company.
The Alliance Army also utilized companies as infantry units, with Twilight Company being one example, although their size was not as strictly defined.