UNSPSC:

The United Nations Standard Products and Services Code is a hierarchical convention that is used to classify all products and services. It is the most efficient, accurate and flexible classification system available today for achieving company-wide visibility of spend analysis, enabling procurement to deliver on cost-effectiveness demands and allowing full exploitation of electronic commerce capabilities.

eOTD:

The eOTD is a dictionary of terminology where terms, definitions and images are linked to concept identifiers, these concept identifiers are used to create encoded descriptions of individuals, organizations, locations, goods and services.

eCl@ss:

eCl@ss is a hierarchical system for grouping materials, products and services according to a logical structure with a level detail that corresponds to the product-specific properties that can be described using norm-conforming properties. Products and services can be allocated to the four-stage, numeric eCl@ss class structure.

NAICS:

NAICS (pronounced nakes), is the North American Industry Classification System. NAICS is used by business and government to classify and measure economic activity in Canada, Mexico and the United States. The NAICS numbering system is a six-digit code. The first five digits are generally (although not always strictly) the same in all three countries. The last digit designates national industries. The first two digits designate the largest business sector, the third digit designates the sub sector, the fourth digit designates the industry group, and the fifth digit designates particular industries.