Ill. Admin. Code tit. 35, § 203.2110
For this Subpart, the definitions in Section 203.2120 through Section 203.2290 apply. When a term is not defined in these Sections, it shall have the meaning given in Subpart I of this Part, Part 211, or in the CAA.
(Source: Added at 49 Ill. Reg. 6237, effective April 23, 2025)