The following words and phrases as used in sections 169.410 to 169.540 , unless a different meaning is plainly required by the context, shall have the following meanings:
(1) "Accumulated contributions" , the sum of all amounts deducted from the compensation of a member and credited to the member's individual account together with interest allowed on such an account;
(2) "Actuarial equivalent" , a benefit of equal value when computed upon the basis of interest and such mortality tables as shall be adopted by the board of trustees;
(3) "Average final compensation" , the highest average annual compensation of the member received for any three consecutive years of credited service of the member's last ten years of credited service or if the member has had less than three years of such credited service, during the member's entire period of credited service;
(4) "Beneficiary" , any person other than a retired member receiving a pension benefit, optional pension benefit or other benefit;
(5) "Board of education" , the board of education or corresponding board having charge of the public schools of the school district other than those public schools which are operated by the board of regents;
(6) "Board of regents" , the board of regents or corresponding board having charge of a public city teacher training school within the school district which was operated by its board of education prior to September 1, 1978;
(7) "Board of trustees" , the board which administers the retirement system;
(8) "Charter school" , any charter school established pursuant to sections 160.400 to 160.420 and located, at the time it is established, within the school district;
(9) "Compensation" , the regular compensation which a member has earned as an employee during any period, excluding, however, any compensation earned by a person who became a member after December 31, 1995, which is in excess of the limitation set forth in Section 401(a)(17) of the Internal Revenue Code;
(10) "Consumer price index" , the Consumer Price Index for All Urban Consumers for the United States, or its successor index, as approved by the board of trustees, as such index is defined and officially reported by the United States Department of Labor, or its successor agency;
(11) "Credited service" , prior service plus membership service plus service purchased pursuant to applicable Missouri statute;
(12) "Employee" , any person regularly employed by (a) the board of education, or (b) the board of trustees, or (c) the board of regents who was employed at a public teacher training school within the school district prior to September 1, 1978, and who did not become a member of the Missouri state employees' retirement system pursuant to section 104.342 , or (d) a charter school. In case of doubt as to whether any person is an employee, the decision of the board of education, or the board of trustees, or the board of regents shall be final and conclusive;
(13) "Employer" , the board of education, the board of trustees, the board of regents or a charter school;
(14) "Medical board" , the board of physicians;
(15) "Member" , a member of the retirement system defined as an:
(a) "Active member" , a person who is an employee;
(b) "Inactive member" , a former active member who has accumulated contributions with the retirement system; or
(c) "Retired member" , a former active member who has retired and is receiving benefits;
(16) "Membership service" , service rendered as an employee for which the employee received compensation. For the purpose of computing creditable service at retirement, membership service shall include a member's accumulated and unused days of sick leave. The decision of the employing board as to the number of accumulated and unused days of sick leave held by a member shall be final and conclusive;
(17) "Pension benefit" or "pension" , monthly payments for life to a retired member or to such beneficiary as is entitled to the payments;
(18) "Prior service" , service prior to the date the system became operative which is credited;
(19) "Public school" , any school for elementary, secondary or higher education, open and public, which is supported and maintained from public funds and which is operated by the board of education of the school district, by the board of regents, or as a charter school as defined pursuant to sections 160.400 to 160.420 ;
(20) "Retired member" , a member receiving a retirement benefit or other benefit;
(21) "Retirement system" , the public school retirement system of a school district;
(22) "School administrator" , an employee whose job classification is included on the school administrators' position schedule of the employing board;
(23) "School district" , any metropolitan school district as defined pursuant to section 160.011 ;
(24) "Teacher" , any teacher, substitute teacher, supervisor, principal, supervising principal, superintendent or assistant superintendent, who shall teach or be employed on a full-time basis in the public schools of a school district or charter school, except those teachers electing to become members of the Missouri state employees' retirement system pursuant to section 104.342 . In case of doubt as to whether any person is a teacher, the decision of the board of education, or the board of regents with respect to individuals within its charge, shall be final and conclusive.