A chair, convener, or seat is an office, authority, or dignity (such as a professorship at a college or university) or the holder of that office (such as the chair of a committee, commission, or board). The office holder is traditionally also called the chairman, but chairwoman and chairperson have become increasingly common. Chair usually refers only to the head of a governing body, while a seat refers to any position in that governing body.

While the term chairman remains in widespread use (especially in predominantly male spheres), chair and chairperson are often used, especially in the United States and Australia in general and in the UK public sector as gender-neutral terms. blank">http://www.bartleby.com/61/85/P0208500.html

A majority of _FTSE 100 companies in the UK have a "chairman," and the boards of most Fortune 500 companies in the U.S. also have a chairman. Less than half of the members of the American Heritage Dictionary accept the use of the word chairman in describing a woman, although the term "Madam Chairman" may be employed. The Random House Unabridged Dictionary (2006) says that chairperson enjoys widespread acceptance and that although some media outlets do not use it, "Chairperson is standard in all varieties of speech and writing."http://dictionary.reference.com/browse/chairperson