Source : Webster's Revised Unabridged Dictionary (1913)

Chair \Chair\, v. t. [imp. & p. pr. {Chaired}; p. pr. & vb. n.
   {Chairing}.]
   1. To place in a chair.

   2. To carry publicly in a chair in triumph. [Eng.]

Chair \Chair\, 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}.]
   1. A movable single seat with a back.

   2. An official seat, as of a chief magistrate or a judge, but
      esp. that of a professor; hence, the office itself.

            The chair of a philosophical school.  --Whewell.

            A chair of philology.                 --M. Arnold.

   3. The presiding officer of an assembly; a chairman; as, to
      address the chair.

   4. A vehicle for one person; either a sedan borne upon poles,
      or two-wheeled carriage, drawn by one horse; a gig.
      --Shak.

            Think what an equipage thou hast in air, And view
            with scorn two pages and a chair.     --Pope.

   5. An iron block used on railways to support the rails and
      secure them to the sleepers.

   {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.

Source : WordNet®

chair
     n 1: a seat for one person, with a support for the back; "he put
          his coat over the back of the chair and sat down"
     2: the position of professor; "he was awarded an endowed chair
        in economics" [syn: {professorship}]
     3: the officer who presides at the meetings of an organization;
        "address your remarks to the chairperson" [syn: {president},
         {chairman}, {chairwoman}, {chairperson}]
     4: an instrument of execution by electrocution; resembles a
        chair; "the murderer was sentenced to die in the chair"
        [syn: {electric chair}, {death chair}, {hot seat}]

chair
     v 1: act or preside as chair, as of an academic department in a
          university; "She chaired the department for many years"
          [syn: {chairman}]
     2: preside over; "John moderated the discussion" [syn: {moderate},
         {lead}]