Most U.S. colleges do not use the term "rector." The terms "president" and "chancellor" are often used for the chief executive of universities and university systems, depending on the institution's statutes or governing documents. Some state university systems have both "presidents" of the constituent institutions and a "chancellor" of the overall system, or vice versa; for example, in the University of California system, each of the ten campuses is headed by a chancellor, while the leader of the system is given the title "president." Colleges and universities, or state systems, also typically have governing boards (akin to a board of directors), which may be referred to by a variety of names, including "board of trustees" and "board of regents," and which are usually led by a chairperson.