This video explains the industry classification system called NAICS and how to determine the NAICS code for an industry.
"The North American Industry Classification System (NAICS, pronounced Nakes) was developed as the standard for use by Federal statistical agencies in classifying business establishments for the collection, analysis, and publication of statistical data related to the business economy of the U.S. "
NAICS (North American Industry Classification System) -- "developed jointly by the U.S., Canada, and Mexico to provide new comparability in statistics about business activity across North America."
Identifying the NAICS for an Industry -- One of the easiest ways to identify the NAICS or SIC for an industry is to look up a company in that industry using one of the business databases. The descriptive information about the company almost always includes a listing of the industry or industries in which the company is engaged.
SIC (Standard Industrial Classification) Manual