The Confederate States Army was the army of the Confederate States of America (or “Confederacy”) while the Confederacy existed during the American Civil War.
As in the Union Army, Confederate soldiers were organized by military specialty. The combat arms included infantry, cavalry and artillery.
The Confederate States Army consisted of several armies. Although fewer soldiers might comprise a squad or platoon, the smallest unit in the Army was a company of 100 soldiers. Ten companies were organized into a regiment, which theoretically had 1,000 men. They were generally referred by number and state, for example 1st Texas, 12th Virginia. To the extent the word “battalion” was used to described a military unit, it referred to a regiment or a near regimental size unit. Four regiments usually formed a brigade, although as the number of men in many regiments became greatly reduced, especially later in the war, more than four were often assigned to a brigade. Occasionally, regiments would be transferred between brigades. Two to four brigades usually formed a division. Two to four divisions usually formed a corps. Two to four corps usually formed an army. Occasionally, a single corps might operate independently as if it were a small army.
Learn more at the wikipedia, Confederate States Army