If you don't know the NAICS/SIC or you're not sure what words will be used to name the industry, then start by looking up information about a specific company engaged in the industry. For example, industry resources might refer to:
and you might spend a lot of time hunting for the right words to describe the category. By looking up descriptive information for Ford Motor Company, you quickly discover:
The same advice holds true when beginning a search for articles providing an overview of an industry or industry trends. Instead of trying to figure out what words will describe the industry, search for the names of three or four major companies engaged in the industry since they're highly likely to be mentioned.
For example, Wal-Mart Stores, Inc. is involved in many different industry sectors, including:
If your intent is to research drug stores as an industry then you're probably not going to search for industry data about "warehouse clubs & superstores".