40 ILCS 5/12-123.1: Surviving spouse.

Surviving spouse: The spouse of an active employee on the date of the employee's death; the spouse of an inactive member on the date of separation from park service, unless the member has subsequent service with another pension fund or retirement system under the Retirement Systems Reciprocal Act and elects to receive a retirement annuity calculated under that Act; the spouse of an annuitant on the date of retirement. If the marriage terminates after the inactive member separates from service or the member retires, the former spouse is no longer eligible for benefits as the surviving spouse. The term "widow" means "surviving spouse" for the purposes of this Article.