5 C.F.R. § 550.803
In this subpart:
Agency has the meaning given that term in section 5596(a) of title 5, United States Code.
Appropriate authority means an entity having authority in the case at hand to correct or direct the correction of an unjustified or unwarranted personnel action, including
Collective bargaining agreement has the meaning given that term in section 7103(a)(8) of title 5, United States Code, and (with respect to members of the Foreign Service) in section 1002 of the Foreign Service Act of 1980 (22 U.S.C. 4102(4) ).
Employee means an employee of an agency. When the term employee is used to describe an individual who is making a back pay claim, it also may mean a former employee.
Grievance has the meaning given that term in section 7103(a)(9) of title 5, United States Code, and (with respect to members of the Foreign Service) in section 1101 of the Foreign Service Act of 1980 (22 U.S.C. 4131 ). Such a grievance includes a grievance processed under an agency administrative grievance system, if applicable.
Pay, allowances, and differentials means pay, leave, and other monetary employment benefits to which an employee is entitled by statute or regulation and which are payable by the employing agency to an employee during periods of Federal employment. Agency and employee contributions to a retirement investment fund, such as the Thrift Savings Plan, are not covered. Monetary benefits payable to separated or retired employees based upon a separation from service, such as retirement benefits, severance payments, and lump-sum payments for annual leave, are not covered.
Unfair labor practice means an unfair labor practice described in section 7116 f title 5, United States Code, and (with respect to members of the Foreign Service) in section 1015 of the Foreign Service Act of 1980 (22 U.S.C. 4115 ).
Unjustified or unwarranted personnel action means an act of commission or an act of omission (i.e., failure to take an action or confer a benefit) that an appropriate authority subsequently determines, on the basis of substantive or procedural defects, to have been unjustified or unwarranted under applicable law, Executive order, rule, regulation, or mandatory personnel policy established by an agency or through a collective bargaining agreement. Such actions include personnel actions and pay actions (alone or in combination).
5 C.F.R. §550.803