48 C.F.R. § 402.101
Acquisition official means an individual who has been delegated authority to manage or to exercise acquisition functions and responsibilities.
Agency head or head of the agency means the Secretary of Agriculture (Secretary), Deputy Secretary, or the Assistant Secretary for Administration (ASA).
Head of the Contracting Activity (HCA) means the official with overall responsibility of one or more USDA contracting activities.
Mission Area senior contracting official means the official designated by the Senior Procurement Executive or Head of the Contracting Activity with specific responsibilities within an individual Mission Area's contracting activity.
Senior Procurement Executive (SPE) means the agency official appointed as such by the Head of the Agency pursuant to Executive Order 12931. The Director, Office of Contracting and Procurement, has been designated as the USDA SPE.
48 C.F.R. §402.101