Employee means, but is not limited to, an individual who fits within one of the following listed groups:
(1) A civil officer or employee in any branch of the Government of the United States, including an officer or employee of an instrumentality wholly owned by the United States pursuant to 5 U.S.C. 8101(1)(A);
(2) An individual rendering personal service to the United States similar to the service of a civil officer or employee of the United States, without pay or for nominal pay, when a statute authorizes the acceptance or use of the service, or authorizes payment of travel or other expenses of the individual pursuant to 5 U.S.C. 8101(1)(B);
(3) An individual, other than an independent contractor or an individual employed by an independent contractor, employed on the Menominee Indian Reservation in Wisconsin in operations conducted under a statute relating to Tribal timber and logging operations on that reservation pursuant to 5 U.S.C. 8101(1)(C);
(4) An individual appointed to a position on the office staff of a former President under section 1(b) of the Act of August 25, 1958 (72 Stat. 838) pursuant to 5 U.S.C. 8101(1)(E); or
(5) An individual selected and serving as a Federal petit or grand juror pursuant to 5 U.S.C. 8101(1)(F).
20 CFR § 10.5
Certain words and phrases found in this part are defined in this section or in the FECA. Some other words and phrases that are used only in limited situations are defined in the later subparts of the regulations in this subchapter.