As used in this chapter, the term:

(1) "Board of regents" means the Board of Regents of the University System of Georgia.

(2) "Board of trustees" means the Board of Trustees of the Teachers Retirement System of Georgia.

(3) "Earnable compensation" means the full rate of regular compensation payable to a participating employee for the employee's normal working time and includes compensation paid to the employee by an employer from grants or contracts made by outside agencies with the employer.

(4) "Participating employee" means an eligible university system employee, as defined in Code Section 47-3-68, who elects to participate in the retirement plan provided for in this chapter pursuant to the provisions of said Code Section 47-3-68.