The following definitions shall be applied to the terms used in this article: (1) "Agreement" shall mean contract and shall include renewals and alterations of a contract; (2) "Political subdivision" shall mean any agency or unit of this State, corporate or otherwise, which is authorized to levy taxes or empowered to cause taxes to be levied; (3) "Services" shall mean such public and municipal functions as are performed for property in and persons residing within a political subdivision; and (4) "Project" shall mean any reforestation project, resettlement project or rural rehabilitation project for resettlement purposes of the United States located within a political subdivision and shall include the persons inhabiting such project.