Classification
A publication,such as Uniform Freight Classification (railroad) or the National Motor Freight Classification (motor carrier), that assigns ratings to various articles and provides bill of lading descriptions and rules.
Source: U.S. Maritime Administration.
Patents are classified (organized) in the U.S. by a system using a 3 digit class and a 3 digit subclass to describe every similar grouping of patent art. A single invention may be described by multiple classification codes.
Source: U.S. Patent and Trademark Office.