Tennessee Code Title 58. Military Affairs, Emergencies and Civil Defense § 58-1-104

(a) The military forces of the state, in conformity with the Constitution of Tennessee, shall be divided into three (3) parts, as follows: the army, the navy and the militia.

(b) The army shall be composed of an army national guard and an air national guard, which forces, together with an inactive national guard, when such is authorized by the laws of the United States and regulations issued pursuant thereto, shall comprise the Tennessee national guard; and the Tennessee state guard, whenever such a state force shall be duly organized, and its reserve.

(c) The navy shall consist of such naval or sea forces as may be duly organized.

(d) The militia shall consist of all able-bodied male citizens who are residents of this state and between eighteen (18) and forty-five (45) years of age and who are not members of the army or navy as hereinabove defined, and who may not otherwise be exempted by the laws of this state or the United States.