As used in this subchapter—

(a) "Secretary" means the Secretary of Education.

(b) "Desegregation" means the assignment of students to public schools and within such schools without regard to their race, color, religion, sex or national origin, but "desegregation" shall not mean the assignment of students to public schools in order to overcome racial imbalance.

(c) "Public school" means any elementary or secondary educational institution, and "public college" means any institution of higher education or any technical or vocational school above the secondary school level, provided that such public school or public college is operated by a State, subdivision of a State, or governmental agency within a State, or operated wholly or predominantly from or through the use of governmental funds or property, or funds or property derived from a governmental source.

(d) "School board" means any agency or agencies which administer a system of one or more public schools and any other agency which is responsible for the assignment of students to or within such system.