For the purposes of this Act:
"Department" means the Department of Revenue.
"Taxpayer" means a person who has received a protestable notice of assessment, a claim denial, or a protestable notice of penalty liability within the Tax Tribunal's jurisdiction pursuant to Section 1-45 of this Act.
"Tax Tribunal" means the Illinois Independent Tax Tribunal established pursuant to Section 1-15 of this Act.
35 ILCS 1010/1-10