In this title the following words have the meanings indicated. “County” means a county of the State and, unless expressly provided otherwise, Baltimore City. “Special retirement or pension system” means a retirement or pension system that: provides retirement or pension benefits; and allows a county executive, county council member, county commissioner, or appointed official to participate. “Special retirement or pension system” does not include: a defined contribution plan with benefits determined by an actuarial computation based on employee contributions and the accrued return on those contributions; or a retirement or pension plan that determines benefit amounts using computations or other specific methods enacted as an ordinance by the governing body.