Q. What is and where can I find a SIC code?

SIC or Standard Industrial Classification code is a numerical classification system used to group/classify similar companies into industries for the purposes of collecting, analyzing, and publishing statistical data related to the U.S. business economy.

Try:

• One of the few government agencies still using the SIC is the Occupational Safety and Health Administration of the U. S. Department of Labor and here is their SIC Code lookup.
• Most company profiles still indicate the primary and secondary SIC codes for a company. Look at the resources listed on the Company Profiles & Directories area of the Company Research Guide to find a company profile.

SIC are superseded by NAICS, but many resources still use the SIC codes.
https://libguides.bentley.edu/industrycodes