750 ILCS 75/10
As used in this Act:
"Certificate" means a document that certifies that the persons named on the certificate have established a civil union in this State in compliance with this Act.
"Civil union" means a legal relationship between 2 persons, of either the same or opposite sex, established pursuant to this Act.
"Department" means the Department of Public Health.
"Officiant" means the person authorized to certify a civil union in accordance with Section 40.
"Party to a civil union" means a person who has established a civil union pursuant to this Act. "Party to a civil union" means, and shall be included in, any definition or use of the terms "spouse", "family", "immediate family", "dependent", "next of kin", and other terms that denote the spousal relationship, as those terms are used throughout the law.
750 ILCS 75/10