55 ILCS 5/2-5003
As used in this Division, unless the context requires otherwise:
"County board" or "board" means the legislative governing body of any county other than Cook County which has adopted the county executive form of government under this Division.
"County board speaker" or "speaker" means the county board member elected by the county board to serve as the lead representative for the county board, and may be referred to as the "county board speaker", "speaker", "county board chair", or "chair".
"County executive" means the county official elected by the voters of any county other than Cook County to be the chief executive officer to administer the county executive form of government under this Division.
"County executive form of government" means that form of government in which the departments of county government are administered by a single county official called the county executive elected at large by the qualified voters of the county. The board shall act as the legislative body of the county under this form of county government.
55 ILCS 5/2-5003