As used in this subchapter:
(1) “Calendar quarter” means the three-month period beginning on January 1, April 1, July 1, or October 1;
(2) “County” means each of the counties of this state;
(3) “Local government” means a city or county;
(4) “Municipality” and “city” mean any city of the first class, city of the second class, or incorporated town in this state; and
(5) “Secretary” means the Secretary of the Department of Finance and Administration in the exercise of those powers, functions, and duties formerly vested in the Commissioner of Revenues of the State of Arkansas which were merged into the Department of Finance and Administration under the provisions of § 25-8-101 et seq., or any of his or her authorized agents.