The following words and phrases as used in sections 87.120 to 87.370, unless a different meaning is plainly required by the context, have the following meanings:
(1) "Accumulated contributions", the sum of all amounts deducted from the compensation of a member and credited to his or her individual account in the members' savings fund together with interest thereon;
(2) "Actuarial equivalent", a benefit of equal value when computed upon the basis of such mortality tables and interest rate as shall be adopted by the board of trustees;
(3) "Average final compensation", the average earnable compensation of the member during his or her last two years of service as a firefighter, or if the firefighter has less than two years of service, then the average earnable compensation of his or her entire period of service;
(4) "Beneficiary", any person in receipt of a retirement allowance or other benefit as provided by sections 87.120 to 87.370;
(5) "Benefit reserve", the present value of all payments to be made on account of any retirement allowance or benefit in lieu of a retirement allowance upon the basis of such mortality tables and interest rate as shall be adopted by the board of trustees;
(6) "Board of trustees", the board provided for in section 87.140 to administer the retirement system;
(7) "City", any city not within a county and adopting the retirement system provided by sections 87.120 to 87.370;
(8) "Creditable service", prior service plus membership service as provided in section 87.135;
(9) "DROP", the deferred retirement option plan provided in section 87.182;
(10) "Earnable compensation", the regular compensation which a member would earn during one year on the basis of the stated compensation for his or her rank or position;
(11) "Firefighter", any officer or employee of the fire department of the city employed by the city for the duty of fighting fires, but does not include anyone employed in a clerical or other capacity not involving fire-fighting duties. In case of doubt as to whether any person is a firefighter within the meaning of sections 87.120 to 87.370, the decision of the board of trustees shall be final;
(12) "Medical board", the board of physicians provided for in section 87.160;
(13) "Member", a member of the retirement system as defined by section 87.130;
(14) "Membership service", service as a firefighter rendered since last becoming a member;
(15) "Prior service", all service as a firefighter rendered prior to the date the system becomes operative which is creditable in accordance with the provisions of section 87.135;
(16) "Retirement allowance", annual payments for life which shall be payable in equal monthly installments or any benefits in lieu thereof granted to a member upon retirement or to a beneficiary;
(17) "Retirement system", the firefighter's retirement system of any city as defined in section 87.125.