battalion

n. [ F. bataillon, fr. It. battaglione. See Battalia. ] 1. A body of troops; esp. a body of troops or an army in battle array. [ archaic ] “The whole battalion views.” Milton. [ 1913 Webster +PJC ]

2. (Mil.) An infantry command of two or more companies, which is the tactical unit of the infantry, or the smallest command which is self-supporting upon the battlefield, and also the unit in which the strength of the infantry of an army is expressed. [ 1913 Webster ]

☞ In the United States army, since April 29, 1898, a battalion consists of four companies, and three battalions form a regiment. The term is also applied to two or more batteries of artillery combined into a single command. [ Webster 1913 Suppl. ]