Source : Webster's Revised Unabridged Dictionary (1913)

Doctor \Doc"tor\, n. [OF. doctur, L. doctor, teacher, fr. docere
   to teach. See {Docile}.]
   1. A teacher; one skilled in a profession, or branch of
      knowledge learned man. [Obs.]

            One of the doctors of Italy, Nicholas Macciavel. --
                                                  Bacon.

   2. An academical title, originally meaning a men so well
      versed in his department as to be qualified to teach it.
      Hence: One who has taken the highest degree conferred by a
      university or college, or has received a diploma of the
      highest degree; as, a doctor of divinity, of law, of
      medicine, of music, or of philosophy. Such diplomas may
      confer an honorary title only.

   3. One duly licensed to practice medicine; a member of the
      medical profession; a physician.

            By medicine life may be prolonged, yet death Will
            seize the doctor too.                 -- Shak.

   4. Any mechanical contrivance intended to remedy a difficulty
      or serve some purpose in an exigency; as, the doctor of a
      calico-printing machine, which is a knife to remove
      superfluous coloring matter; the doctor, or auxiliary
      engine, called also {donkey engine}.

   5. (Zo["o]l.) The friar skate. [Prov. Eng.]

   {Doctors' Commons}. See under {Commons}.

   {Doctor's stuff}, physic, medicine. --G. Eliot.

   {Doctor fish} (Zo["o]l.), any fish of the genus {Acanthurus};
      the surgeon fish; -- so called from a sharp lancetlike
      spine on each side of the tail. Also called {barber fish}.
      See {Surgeon fish}.