Immediate annuity
(j) Immediate annuity means (1) as applied to a retired employee, an annuity which begins to accrue not later than 1 month after the date of the separation from the service on which title to the annuity is based; and (2) as applied to a survivor, an annuity which begins to accrue not later than 1 month (i) after the date of death of the employee or annuitant whose service forms the basis for the annuity, or (ii) after the birth of a posthumous child of such an employee or annuitant.