5 C.F.R. § 591.102
Agency means an "Executive agency," as defined in 5 U.S.C. 105 .
Employee means an employee in or under an agency.
Category of employees means any group of employees designated by an agency that has the same basic uniform requirements.
Head of agency means the head of an agency or an official who has been delegated the authority to act for the head of the agency in the matter concerned.
Uniform means a specified article or articles of clothing that may include, but is not limited to, such items as shoes, boots, hats, shirts, slacks, skirts, or outerwear an employee is required by an agency to wear to provide a distinctive and easily identifiable appearance in performing his or her job. A "uniform" does not include protective equipment required for the employee's safety under 5 U.S.C. 7903 or normal business or work attire purchased at the discretion of the employee.
Year means any period of 12 consecutive months designated by an agency as the basis for applying the maximum uniform allowance rates established under this part.
5 C.F.R. §591.102