National Stock Number
A 13-digit number the federal government assigns to a specific, recurringly procured item of supply, combining a 4-digit Federal Supply Classification code with a 9-digit National Item Identification Number. NSNs let the government uniquely identify, catalog, and reorder the same item across the supply chain regardless of manufacturer or contract.
Related terms
International Organization for Standardization
ISOAn independent, non-governmental body that develops voluntary international standards covering areas like quality management (ISO 9001), information security (ISO 27001), and risk management. In GovCon, ISO certifications are frequently cited in proposals as evidence of mature, auditable processes, and some solicitations require or score them.
North American Industry Classification System
NAICSA six-digit code, maintained by the U.S. Census Bureau under OMB, that classifies businesses by their primary line of activity. In federal contracting, the contracting officer assigns a NAICS code to each solicitation to set the applicable small business size standard and determine who's eligible to compete or claim a set-aside.
Product Service Code
PSCA four-character code, maintained by GSA in the PSC Manual, that identifies what a contract actually buys (a product, service, or R&D effort), as distinct from NAICS, which classifies the vendor's industry. PSCs are typically reported in FPDS on contract actions and are commonly used to research and analyze past procurement activity by category.
United Nations Standard Products and Services Code
UNSPSCA global, hierarchical classification system (segment, family, class, commodity) that codes products and services for procurement and spend-analysis purposes, jointly developed with the UN Development Programme. It shows up less often in day-to-day federal solicitations than NAICS or PSC, but appears in some agency catalogs, e-procurement systems, and international sourcing contexts.
