Ariz. Admin. Code § 15-10-101
For purposes of this Article:
1. "ALJ" means an administrative law judge who issues decisions on behalf of the Office of Administrative Hearings established by A.R.S. § 41-1092.01.
2. "Day" means a calendar day. If the last day for filing a document under the provisions of this Article falls on a Saturday, Sunday, or legal holiday, the document is considered timely if filed on the following business day.
3. "Department" means the Arizona Department of Revenue as represented by personnel of the applicable section or area.
4. "Notice" means a written notification, issued by the Department, of a tax assessment, refund denial, or any other action taken or proposed to be taken that is subject to appeal as a contested case or an appealable agency action under A.R.S Title 41, Chapter 6.
5. "Petition" means a written request for hearing, correction, or redetermination, including all applicable attachments.
6. "Petitioner" means the taxpayer or the representative of the taxpayer who files a petition.
7. "Refund denial" means a taxpayer's claim for a refund of tax, penalty, interest, or refundable credit that has been denied by the Department.
8. "Tax assessment" means any tax issue whether associated with a proposed amount due or the application of penalties and interest.
Ariz. Admin. Code § R15-10-101