A fifth quinary sector has been proposed encompassing nonprofit activities. The economy is also broadly separated into public sector and private sector, with industry generally categorized as private. Industries are also any business or manufacturing.
See also military-industrial complex, arms industry, military industry and modern warfare.
Industry classification systems used by the government commonly divide inustry into three sectors: agriculture, manufacturing, and services. The primary sector of industry is agriculture, mining and raw material extraction. The secondary sector of industry is manufacturing.
Sometimes one talks about a quaternary sector of industry, consisting of intellectual services such as R&D.
Source: Wikipedia > Industry
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