Industry Codes such are used in business to standardize economic data and are very important in financial reporting. Here are some you may need to know:
NAICS - North American Industry Classification System (NAICS), used by Federal statistical agencies in "classifying business establishments for the purpose of collecting, analyzing, and publishing statistical data related to the U.S. business economy" (U.S. Census Bureau).
SIC - Standard Industrial Classification (SIC), used by some registries such as the U.S. Securities and Exchange Commission (SEC), instead of NAIC
NTEE - National Taxonomy of Exempt Entitities (NTEE), specifically classifies non-profit organizations
Use the resources listed below to look up NAIC, SIC, and NTEE codes: