The primary industry mainly refers to industries that produce ingredients and some other biological materials, including planting, forestry, animal husbandry, aquaculture, and other industries that directly use natural objects as production objects.

The secondary industry mainly refers to the processing and manufacturing industry, which utilizes the basic materials provided by nature and the primary industry for processing.

The tertiary industry refers to industries other than the primary and secondary industries, and has a broader scope, mainly including the transportation industry, communication industry, commerce, catering industry, finance industry, education industry, public **** services and other non-material production sectors.

Expanded Information

Social Background of the Three Major Industries:

In the post-war period, with the socio-economic and scientific advances, the ratio of output value and employed persons in each sector of the national economy has been changing constantly. The trend of change was: at first, the proportion of the primary industry was declining, the proportion of the secondary industry was rising, and the proportion of the tertiary industry was also rising; then the proportions of the material production sectors, including the primary and secondary industries, were declining to varying degrees, and the proportion of the tertiary industry continued to rise.

This trend of change is more prominent in developed countries. The proportion of output value and employed population of tertiary industry in developed countries is generally above 50%, becoming the largest and fastest growing industry.

Baidu Encyclopedia-Three Major Industries