North American Industry Classification System (NAICS) Canada 2017 Version 3.0
The structure of NAICS is hierarchical. It is composed of five levels.
level 1: sectors (two-digit codes)
level 2: subsectors (three-digit codes)
level 3: industry groups (four-digit codes)
level 4: industries (five-digit codes)
level 5: Canadian industries (six-digit codes)