The chairman is the highest officer of an organized group such as a board, committee, or deliberative assembly. The person holding the office is typically elected or appointed by the members of the group. The chairman presides over meetings of the assembled group and conducts its business in an orderly fashion. When the group is not in session, the officer's duties often include acting as its head, its representative to the outside world and its spokesperson.

Other terms sometimes used for the office and its holder include presiding officer, president, moderator, chair, and convenor. The chairman of a parliamentary chamber is often called the speaker. Though chairwoman is sometimes used as a female counterpart to chairman, the terms chair and chairperson are sometimes used to avoid gendered titles altogether. The National Association of Parliamentarians does not approve using "chairperson". In the United States, the presiding officer of the "lower" house of a legislative body, such as the House of Representatives, is frequently titled the Speaker, while the "upper" house, such as the Senate, is commonly chaired by a President.

A chair is a raised surface used to sit on, commonly for use by one person. Chairs are most often supported by four legs and have a back; however, a chair can have three legs or could have a different shape.

A chair without a back or arm rests is a stool, or when raised up, a bar stool. A chair with arms is an armchair and with folding action and inclining footrest, a recliner. A permanently fixed chair in a train or theater is a seat or airline seat; when riding, it is a saddle and bicycle saddle, and for an automobile, a car seat or infant car seat. With wheels it is a wheelchair and when hung from above, a swing.

A chair for more than one person is a couch, sofa, settee, or "loveseat"; or a bench. A separate footrest for a chair is known as an ottoman, hassock or pouffe.

The chair is of extreme antiquity and simplicity, although for many centuries it was an article of state and dignity rather than an article of ordinary use. "The chair" is still extensively used as the emblem of authority in the House of Commons in the United Kingdom and Canada, and in many other settings.

An official is someone who holds an office (function or mandate, regardless whether it carries an actual working space with it) in an organization or government and participates in the exercise of authority (either his own or that of his superior and/or employer, public or legally private).

A government official or functionary is an official who is involved in public administration or government, through either election, appointment, selection, or employment. A bureaucrat is a member of the bureaucracy. An elected official is a person who is an official by virtue of an election. Officials may also be appointed ex officio (by virtue of another office, often in a specified capacity, such as presiding, advisory, secretary). Some official positions may be inherited.

A person who currently holds an office is referred to as an incumbent.

The word official as a noun has been recorded since the Middle English period, first seen in 1314.^{[citation needed]} It comes from the Old French official (12th century), from the Latin officialis ("attendant to a magistrate, public official"), the noun use of the original adjective officialis ("of or belonging to duty, service, or office") from officium ("office"). The meaning "person in charge of some public work or duty" was first recorded in 1555. The adjective is first attested in English in 1533, via the Old French oficial.