Sectorclassification use of NAICS sector categories to describe groups of similar businesses. A sector classification consists of the NAICS Short Title text that is a description and accompanying 2-digit NAICS industry code number. Sectors group many more detailed NAICS categories according to similarities in their business activities. Groupings are hierarchical and detailed in NAICS code numbers. For example, the NAICS RetailTrade Sector is NAICS Code 44-45. It includes more detailed industry classifications, and includes such as Home Centers (NAICS 444110) and Fish and Seafood Markets (NAICS 445220).