what are the categorization by industry in economics? I wanted to know what industries are there from an economics point of view, and how each industry branches into different parts. Just categories and names will do , or if you can point to a resource please do.
Several countries have it defined in their tax code, or by the national statistics institute, or the central bank. Stock exchhanges also define industry categories.

For general purposes or international comparisons you can use the categories defined by the world bank (see also in word version), or from the United Nations.