From the perspective of capital relationship, the fund refers to the funds specially used for specific purposes and independently accounted for. Among them, including endowment insurance fund, retirement fund, relief fund, education reward fund, etc. In various countries, there are also special financial funds, collective welfare funds for employees, key construction funds for energy and transportation, and budget adjustment funds unique to China.

In terms of organizational nature, a fund refers to an institution or organization that manages and operates funds dedicated to specific purposes and conducts independent accounting. Such fund organizations can be non-legal institutions (such as financial special funds, college education incentive funds, insurance funds, etc.). ), public institutions (such as Soong Ching Ling Children's Foundation in China, Sun Economics Prize Foundation, Mao Dun Literature Prize Foundation, Ford Foundation and Huo Burridge Foundation in the United States, etc. ) or corporate institutions.