COMMON INDUSTRY NO

Common Industry No most likely refers to the "Not Elsewhere Classified" (n.e.c.) category within the Standard Industrial Classification (SIC) code system. This code is used for industries or business activities that do not fit into any of the more specific existing classifications.
In other words, it means "other" or "miscellaneous" within a broader category.

For example, SIC code "1520" covers "General contractors and operative builders," but the designation "1520 n.e.c." or "1520 Other" would be used for contractors that do not fall into any of the more specific categories within this section.