5 C.F.R. § 7201.103
(b) In addition to approval under paragraph (a) of this section, an employee must obtain prior written approval from the Designated Agency Ethics Official or designee to engage in:
(d) For purposes of this section, “employment” means any form of non-Federal employment or business relationship involving the provision of personal services by the employee. It includes, but is not limited to personal services as an officer, director, employee, agent, attorney, consultant, contractor, general partner, trustee, teacher or speaker. It includes writing when done under an arrangement with another person for production or publication of the written product. It does not, however, include participation in the activities of a nonprofit charitable, religious, professional, social, fraternal, educational, recreational, public service or civic organization unless: