n An item of furniture used to sit on or in, comprising a seat, legs or wheels, back, and sometimes arm rests, for use by one person. Compare stool, couch, sofa, settee, loveseat and bench.
n (music) The seating position of a particular musician in an orchestra.
n (rail transport) An iron block used on railways to support the rails and secure them to the sleepers, and similar devices.
n (chemistry) One of two possible conformers of cyclohexane rings (the other being boat), shaped roughly like a chair.
n (education) A distinguished professorship at a university.
n A vehicle for one person; either a sedan borne upon poles, or a two-wheeled carriage drawn by one horse; a gig.
n The seat or office of a person in authority, such as a judge or bishop.
v (transitive) To act as chairperson at; to preside over.
v (transitive) To carry in a seated position upon one's shoulders, especially in celebration or victory.
v (transitive, Wales, UK) To award a chair to (a winning poet) at a Welsh eisteddfod.
n (often with definite article) Chairperson.
n (fandom slang) The ship of characters Chuck Bass and Blair Waldorf of the Gossip Girl series.
n (often with definite article, also written Chair) Clipping of chairperson. [A chairman or chairwoman, someone who presides over a meeting, board, etc.]
n (informal, with the) Ellipsis of electric chair (“device used for performing execution”). [A chair-like device used for performing execution by electrocution.]