What are SIC and NAICS codes?
Both Standard Industrial Classification (SIC) and North American Industrial Classification System (NAICS) codes identify a firm's primary business activity. For example a firm with SIC 571 primarily sells retail furniture. A firm with NAICS 311 is primarily engaged in food manufacturing.
NAICS codes provide a greater level of detail about a firm's activity than SIC codes.
NOTE: SIC is referred to by its individual acronym's letters (S I C). NAICS rhymes with snakes.