HSN stands for Harmonized System of Nomenclature. It is a system for classifying commodities created by the World Customs organization. U.S. LTL shipping, however, uses NMFC classifications instead.
CWT stands for hundredweight. LTL shipments are priced “per 100 pounds,” “cwt,” or “per hundredweight.” This means that a 400 lb shipment priced at $25 CWT would cost $100, not including accessories or specialty services.
NMFC freight subclasses are used to differentiate among commodities of the same type. For example, one NMFC code for chairs/stools is 82790. Subclasses 82790-1 and 82790-11, despite have the same base NMFC code, fall into two different freight classes.