815 ILCS 308/10
As used in this Act:
"Automotive collision and body repair" means all repairs that are commonly performed by a body repair technician to restore a motor vehicle damaged in a crash or collision to a condition similar to the motor vehicle condition prior to the damage or deterioration including, but not limited to, the diagnosis, installation, exchange, repair, or refinishing of exterior body panels, trim, lighting, and structural chassis. The term does not include commercial fleet repair or maintenance transactions involving 2 or more motor vehicles or ongoing service or maintenance contracts involving motor vehicles used primarily for business purposes.
"Automotive collision and body repair facility" means a person, firm, association, or corporation that for compensation engages in the business of cosmetic repair, structural repair, or refinishing of motor vehicles with defect related to crash or collision.
"New part" means a part or component manufactured or supplied by the original motor vehicle manufacturer in an unused condition.
"Used part" means an original motor vehicle manufacturer part or component removed from a motor vehicle of similar make, model, and condition without the benefit of being rebuilt or remanufactured.
"Rebuilt part" or "reconditioned part" means a used part that has been inspected and remanufactured to restore functionality and performance.
"Aftermarket part" means a new part that is not manufactured or supplied by the original motor vehicle manufacturer for addition to, or replacement of, exterior body panel or trim.
815 ILCS 308/10