The chairman is the highest office of a group such as a board, committee, or other corporate entity. The person holding the office is typically elected or appointed by the members of the group. The chairman presides over meetings and the chairman's duties often includes acting as its head and its representative.
The term is most universally to denote the head of a board of directors of a corporation ("chairman of the board"). The position is technically more senior to a chief executive officer ("CEO") who reports to a board of directors, and usually directly to the chairman, if the two positions are separate. In some public companies, the chairmanship is separate from the CEO to provide better governance for shareholders of the CEO.
In recent times, gender-equality groups have sought to "man-down" or neutralize the "man" in "chairman" by coining new positions such as "chair" or "chairperson" in lieu of "chairman."