In this article, unless the context otherwise requires:
1. "Administrative agency" or "agency" means every agency, board, commission, department or officer authorized by law to exercise rule-making powers or to adjudicate contested cases, whether created by constitutional provision or legislative enactment. Except as provided in section 33-1905, administrative agency or agency does not include an agency in the judicial or legislative departments of the state government, any political subdivision or municipal corporation or any agency of a political subdivision or municipal corporation.
2. "Administrative decision" or "decision" means any decision, order or determination of an administrative agency that is rendered in a case, that affects the legal rights, duties or privileges of persons and that terminates the proceeding before the administrative agency. In all cases in which a statute or a rule of the administrative agency requires or permits an application for a rehearing or other method of administrative review, and an application for a rehearing or review is made, no administrative decision of such agency is final as to the party applying for the rehearing or review until the rehearing or review is denied or the decision on rehearing or review is rendered. Administrative decision or decision does not include either:
(a) Rules, standards or statements of policy of general application issued by an administrative agency to implement, interpret or make specific the legislation enforced or administered by it unless the rule, standard or statement of policy is involved in a proceeding before the agency and its applicability or validity is in issue in the proceeding.
(b) Rules concerning the internal management of the agency and not affecting private rights or interests.