For the purposes of this chapter:
(1) "Employee" includes all officers and employees of the state or its political subdivisions except officials compensated on a fee basis;
(2) "Employment" means any service performed by an employee in the employ of the state, or any political subdivision thereof, for such employer, except (a) service which in the absence of an agreement entered into under this chapter would constitute "employment" as defined in the social security act; or (b) service which under the social security act may not be included in an agreement between the state and the secretary of health, education, and welfare entered into under this chapter;
(3) "Federal insurance contributions act" means subchapter A of chapter 9 of the federal internal revenue code of 1939 and subchapters A and B of chapter 21 of the federal internal revenue code of 1954, as such codes have been and may from time to time be amended; and the term "employee tax" means the tax imposed by section 1400 of such code of 1939 and section 3101 of such code of 1954;
(4) "Political subdivision" includes an instrumentality of the state, of one or more of its political subdivisions, or of the state and one or more of its political subdivisions. Such term also includes a proprietary enterprise acquired, purchased, or originated by the state or any of its political subdivisions subsequent to December, 1950. Such a subdivision may elect to accept federal OASI coverage under this chapter;
(5) "Secretary of health, education, and welfare" includes any individual to whom the secretary of health, education, and welfare has delegated any of his or her functions under the social security act with respect to coverage under such act of employees of states and their political subdivisions, and with respect to any action taken prior to April 11, 1953, includes the federal security administrator and any individual to whom such administrator has delegated any such function;
(6) "Wages" means all remuneration for employment as defined herein, including the cash value of all remuneration paid in any medium other than cash, except that such term shall not include that part of such remuneration which, even if it were for "employment" within the meaning of the federal insurance contributions act, would not constitute "wages" within the meaning of that act.