As used in this article, unless the context otherwise requires:(1) 'Department' means the department of revenue.(2) 'Executive director' or 'executive director of the department of revenue' means the executive director of the department of revenue and includes the head of any group, division, or subordinate department, as appointed in accordance with article 35 of title 24, C.R.S., whenever the executive director specifically authorizes the group, division, or subordinate department head to act on his or her behalf.(3) 'Person' includes any individual, firm, corporation, partnership, limited liability company, joint venture, estate, trust, or group or combination acting as a unit.(4) 'Taxpayer' includes a person against whom a deficiency is being asserted, whether or not he has paid any of the tax in issue prior thereto.L. 65: p. 1148, § 2. C.R.S. 1963: § 138-9-15. L. 76: (1) amended and (1.5) added, p. 777, § 2, effective July 1. L. 77: Entire section R&RE, p. 1765, § 1, effective June 19. L. 90: (3) amended, p. 450, § 28, effective April 18. L. 93: (2) amended, p. 1239, § 13, effective July 1. L. 2000: (2) amended, p. 1639, § 18, effective June 1.