The lexicon of the top500 ( The Encyclopedia for Classification Codes ) explains the codes and definitions in the world of economical classifications.
NAICS Code 3272 Glass and Glass Product Manufacturing
The NAICS Code 3272 is described as
Glass and Glass Product Manufacturing It belongs to the code group
NAICS Code 327 Nonmetallic Mineral Product Manufacturing
To this Code "3272" belongs the sub codes
NAICS Code 32721: Glass and Glass Product Manufacturing