5 C.F.R. § 831.2001
Court order or decree means the order or decree of any court of any State, the District of Columbia, the Commonwealth of Puerto Rico, Guam, the Northern Mariana Islands, the Virgin Islands or any Indian court, as defined section 8331(24) of title 5, United States Code.
Current spouse means a person who is married to the employee or Member at the time the application for refund is filed.
Duly appointed representative of the deceased employee's, separated employee's, retiree's, survivor's or Member's estate means an individual named in an order of a court having jurisdiction over the estate of the deceased which grants the individual the authority to receive, or the right to possess, the property of the deceased; and also means, where the law of the domicile of the deceased has provided for the administration of estates through alternative procedures which dispense with the need for a court order, an individual who demonstrates that he or she is entitled to receive, or possess, the property of the deceased under the terms of those alternative procedures.
Former spouse means a living person who was married for at least 9 months to an employee or Member who had performed at least 18 months of creditable service in a position covered by the retirement system.
Retirement system means the civil service retirement system as described in subchapter III of chapter 83 of title 5, United States Code.
5 C.F.R. §831.2001