INFANTRY
Squad: any small number of men, usually 7, under command of a corporal. Platoon: a subdivision, usually half, of a company under a lieutenant. Company: from 83 to 125 men under a captain. Battalion: 2 or more, usually four, companies under a major. Regiment: 10 companies—or 3 battalions of 4 companies each—under a colonel or a lieutenant-colonel. Brigade: 3 to 5 regiments under a brigadier-general. Division: 2 to 5 brigades under a major-general. Army corps: 2 or more divisions under a major-general or a lieutenant-general,—organized as a complete army and sufficient in itself for all the operations of war.