(a) As used in this part, unless the context otherwise requires:

(1) “Actuarially determined contribution” (ADC), formerly known as the “actuarially required contribution” means the actuarially determined annual required contribution that incorporates both the normal cost of benefits and the amortization of the pension plan's unfunded accrued liability;

(2) “Pension plan” means the defined benefit pension plan established and maintained by a political subdivision for its employees, excluding a political subdivision's participation in the Tennessee consolidated retirement system pursuant to title 8, chapters 34–37. The term “pension plan” shall include all pension plans that are open or closed to membership, and shall also include the plural, referring to any and all pension plans provided by a political subdivision;

(3) “Political subdivision” means any local governmental entity, including, but not limited to any municipality, metropolitan government, county, utility district, school district, public building authority, housing authority, emergency communications district, and development district created and existing pursuant to the laws of this state, or any instrumentality of government created by any one (1) or more of the named local governmental entities;

(4) “Political subdivision employee” means any person in the employ of a political subdivision who participates in the political subdivision's pension plan;

(5) “Unfunded accrued liability” means the actuarially determined accrued liabilities of the pension plan that are greater than the actuarially determined value of the pension plan assets.