In this subtitle the following words have the meanings indicated. “Employees’ system” has the meaning stated in § 31–101 of this title. “Legislative body” has the meaning stated in § 31–101 of this title. “Local pension system” means a retirement or pension system established by the legislative body of an eligible governmental unit that is a qualified plan under § 401(a) of the Internal Revenue Code and provides a defined benefit to its participants. “State system” has the meaning stated in § 20–101(pp) of this article. “Withdrawal date” means the date that a withdrawal by a participating governmental unit from a State system takes effect.