Pla*toon" (?), n. [F. peloton a ball of thread, a knot or group of men, a platoon, from pelote a ball formed of things wound round. See Pellet.] (Mil.) (a) Formerly, a body of men who fired together; also, a small square body of soldiers to strengthen the angles of a hollow square. (b) Now, in the United States service, half of a company.