The objects and purposes for which appropriations shall be made in municipalities specified in Section 8-2-1 are classified and standardized by the following items, and by such items shall be designated in the budget document, and the annual appropriation ordinance:
An appropriation in one or more of the items above specified shall be construed in accordance with the definitions and limitations specified in Sections 8-2-1 through 8-2-8, unless the appropriation ordinance otherwise provides. An appropriation for a purpose other than one specified and defined in this section and in Section 8-2-5 may be made only as an additional, separate and distinct item, specifically stating the object and purpose thereof.
65 ILCS 5/8-2-4