48 C.F.R. § 8.401
As used in this subpart-
Ordering activity means an activity that is authorized to place orders, or establish blanket purchase agreements (BPA), against the General Services Administration's (GSA) Multiple Award Schedule contracts. A list of eligible ordering activities is available at http://www.gsa.gov/schedules (click "For Customers Ordering from Schedules" and then "Eligibility to Use GSA Sources").
Multiple Award Schedule (MAS) means contracts awarded by GSA or the Department of Veterans Affairs (VA) for similar or comparable supplies, or services, established with more than one supplier, at varying prices. The primary statutory authorities for the MAS program are 41 U.S.C. 152(3) , Competitive Procedures, and 40 U.S.C. 501 , Services for Executive Agencies.
Requiring agency means the agency needing the supplies or services.
Schedules e-Library means the on-line source for GSA and VA Federal Supply Schedule contract award information. Schedules e-Library may be accessed at http://www.gsa.gov/elibrary.
Special Item Number (SIN) means a group of generically similar (but not identical) supplies or services that are intended to serve the same general purpose or function.
48 C.F.R. §8.401