40 ILCS 5/16-121
"Salary": The actual compensation received by a teacher during any school year and recognized by the system in accordance with rules of the board. For purposes of this Section, "school year" includes the regular school term plus any additional period for which a teacher is compensated and such compensation is recognized by the rules of the board.
In the case of a person who first becomes a member on or after the effective date of this amendatory Act of the 98th General Assembly, "salary" shall not include any payment for unused sick or vacation time.
Notwithstanding any other provision of this Code, the annual salary of a Tier 1 member for the purposes of this Code shall not exceed, for periods of service on or after the effective date of this amendatory Act of the 98th General Assembly, the greater of (i) the annual limitation determined from time to time under subsection (b-5) of Section 1-160 of this Code, (ii) the annualized salary of the Tier 1 member on that effective date, or (iii) the annualized salary of the Tier 1 member immediately preceding the expiration, renewal, or amendment of an employment contract or collective bargaining agreement in effect on that effective date.
40 ILCS 5/16-121