The Collaborative International Dictionary of English v.0.48:

Chair \Chair\ (ch[^a]r), n. [OE. chaiere, chaere, OF. chaiere,
   chaere, F. chaire pulpit, fr. L. cathedra chair, armchair, a
   teacher's or professor's chair, Gr. ? down + ? seat, ? to
   sit, akin to E. sit. See Sit, and cf. Cathedral,
   chaise.]
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   1. A movable single seat with a back.
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   2. An official seat, as of a chief magistrate or a judge, but
      esp. that of a professor; hence, the office itself.
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            The chair of a philosophical school.  --Whewell.
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            A chair of philology.                 --M. Arnold.
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   3. The presiding officer of an assembly; a chairman; as, to
      address the chair.
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   4. A vehicle for one person; either a sedan borne upon poles,
      or two-wheeled carriage, drawn by one horse; a gig.
      --Shak.
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            Think what an equipage thou hast in air,
            And view with scorn two pages and a chair. --Pope.
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   5. An iron block used on railways to support the rails and
      secure them to the sleepers.
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   Chair days, days of repose and age.

   To put into the chair, to elect as president, or as
      chairman of a meeting. --Macaulay.

   To take the chair, to assume the position of president, or
      of chairman of a meeting.
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