40 ILCS 5/8-123
"Municipal pension fund": Any pension fund created and operated under "An Act to provide for the formation and disbursements of a pension fund in cities, villages and incorporated towns having a population exceeding 100,000 inhabitants for municipal employees appointed to their positions, under and by virtue of an Act entitled, 'An Act to regulate the civil service of cities', approved and in force March 20, 1895, and for those who are appointed prior to the passage of said Act and who are now in the service of such city, village or town", approved May 31, 1911, as amended, or under "An Act to provide for the formation and disbursement of a public school employees' pension fund in cities having a population exceeding one hundred thousand inhabitants", approved May 15, 1903, as amended.
40 ILCS 5/8-123