Do you mean NAICS? That stands for "North American Industry Classification System." That is a service of a US Census Bureau department that assigns business codes to various types of businesses, mainly for statistical and analytical purposes.
In what context are you asking? Do you have a self-employed business that needs to enter a business code on a Schedule C, for example? If you are using Live Deluxe, that edition cannot prepare Schedule C. In the paid Online editions, only Self-Employed Edition can prepare Schedule C.
Live Deluxe is the upgraded version of Online Deluxe that includes live expert help from a CPA/EA during return return preparation and a final review of your return prior to filing.