5 C.F.R. § 841.302
In this subpart-
Employee means an employee as defined in section 8401(11) of title 5, United States Code, and a Member as defined in section 8401(20) of title 5, United States Code. Employee includes a person who had applied for retirement under FERS but had not been separated from the service prior to his or her death even if the person's retirement would have been retroactively effective upon separation.
FERS means the Federal Employees Retirement System as described in chapter 84 of title 5, United States Code.
MSPB means the Merit Systems Protection Board described in chapter 12 of title 5, United States Code.
Retiree means a former employee or Member who is receiving recurring payments under FERS based on service by the employee or Member. Retiree, as used in this subpart, does not include a current spouse, former spouse, child, or person with an insurable interest receiving a survivor annuity. Retiree for purposes of determining a person's status at the time of death means that the person had been separated from the service and had met all the requirements to receive an annuity including having filed an application for the annuity prior to his or her death.
Separated employee means a former employee or Member who has been separated from the service but who has not met all the requirements for retirement under FERS or who has not filed an application for retirement under FERS.
Survivor means a person entitled to benefits under part 843 or 846 of this chapter based on the death of an employee, separated employee, retiree, or survivor.
5 C.F.R. §841.302