Statute 16: Faculty may retire at age 55. A Faculty member who retires from a position on indefinite tenure or who retires from a Faculty position after serving as a Faculty member for 20 years shall be designated a Member Emeritus of the faculty.
To read this Statute in context, please see the University of Chicago's Articles of Incorporation, Bylaws, and Statutes. Note that the Statutes do change, and the current edition (dated May 30, 2018) differs from older versions and will likely differ from versions yet to be approved.