Ariz. Admin. Code § 15-2D-101
In addition to the definitions provided in A.R.S. §§ 43-104, 43-1101, and 43-1131, the following definitions apply to this Subchapter:
"Allocation" means the assignment of nonbusiness income to a particular state.
"Apportionment" means the division of business income between states by the use of a formula that contains apportionment factors.
"Arizona affiliated group" has the same meaning as prescribed in A.R.S. § 43-947(I).
"Business activity" means transactions and activity occurring in the regular course of a particular trade or business of a taxpayer.
"Combined return" means a corporate income tax return filed by a group of commonly owned corporations or businesses that constitute a unitary business, except that a combined return does not include either a foreign corporation that is not itself subject to a tax imposed by A.R.S. Title 43, or an insurance company that is exempt under A.R.S. § 43-1201.
"Consolidated return" means a corporate income tax return filed by an Arizona affiliated group under A.R.S. § 43-947.
"Employee" means any officer of a corporation; or any individual who, under the usual common-law rules applicable in determining the employer-employee relationship, has the status of an employee.
"Incidental to" means occurring in, or associated with, the normal, typical, or customary operations of the particular trade or business under consideration.
"Sales" means all gross receipts derived by a taxpayer from transactions and activity in the regular course of a trade or business and includes all gross receipts of the taxpayer not allocated under A.R.S. §§ 43-1134 through 43-1138.
"Unitary business" means an entity, group of entities, or components of an entity whose basic operations are substantially integrated and interdependent. The determination of whether an entity, group of entities, or components of an entity constitute a unitary business is made under R15-2D-401.
Ariz. Admin. Code § R15-2D-101