5 U.S.C. § 3581

1. (1)“agency” means—
   1. (A)an Executive agency;
   2. (B)a military department; and
   3. (C)an employing authority in the legislative branch;
2. (2)“employee” means an employee in or under an agency;
3. (3)“international organization” means a public international organization or international-organization preparatory commission in which the Government of the United States participates;
4. (4)“transfer” means the change of position by an employee from an agency to an international organization; and
5. (5)“reemployment” means—following a term of employment not extending beyond the period named by the head of the agency at the time of consent to transfer or, in the absence of a named period, not extending beyond the first 5 consecutive years, or any extension thereof, after entering the employ of the international organization.
   1. (A)the reemployment of an employee under section 3582(b) of this title; or
   2. (B)the reemployment of a Congressional employee within 90 days from his separation from an international organization;