In many business databases, one may search using the NAICS Classification System.
"The North American Industry Classification System (NAICS) is a numbering system used by Federal statistical agencies to classify and compare business establishments for the purpose of collecting, analyzing, and publishing statistical data related to the U.S. business economy.
NAICS was developed under the auspices of the Office of Management and Budget (OMB), and adopted in 1997 to replace the Standard Industrial Classification (SIC) system. It was developed ...to allow for a high level of comparability in business statistics among the North American countries."
from the NAICS page of the U. S. Census web page