As used in this title:
(1) “Board” means the Tax Appeal Board.
(2) “Department” means the Department of Finance.
(3) “Notice,” “notification” or “receipt,” required to be given or provided for by this title, means a written notice, notification or receipt, contained in a sealed envelope, addressed to the taxable at the last known address and deposited in the United States mails unless delivered to the taxable in person or to a representative or agent.
(4) “Secretary” and “Secretary of Finance” mean the Secretary of Finance or a duly authorized designee; provided, that any such delegation of authority is consistent with Chapter 83 of Title 29.
(5) “Taxable” means any person, fiduciary, association of persons, syndicate, joint venture or copartnership subject to making return or to payment of tax imposed by this title.