In many nations, the law stipulates that the board of a company must contain some given ratio of "outside directors." These persons are well-known professionals who are not necessarily shareholders in the company on whose board they sit, but who nonetheless have the power to speak on and check the company's major policy decisions.
所謂外部董事，就是經由立法程序，規定企業董事會內須有一定比例、具有社會名望的專業人士加入，這些人不必是公司股東，但卻具有在公司重大決策上發言、制衡的權力。