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}.

Doctor \Doc"tor\, v. t. [imp. & p. p. {Doctored}; p. pr. & vb.
   n. {Doctoring}.]
   1. To treat as a physician does; to apply remedies to; to
      repair; as, to doctor a sick man or a broken cart.
      [Colloq.]

   2. To confer a doctorate upon; to make a doctor.

   3. To tamper with and arrange for one's own purposes; to
      falsify; to adulterate; as, to doctor election returns; to
      doctor whisky. [Slang]

Doctor \Doc"tor\, v. i.
   To practice physic. [Colloq.]

Source : WordNet®

doctor
     n 1: a licensed medical practitioner; "I felt so bad I went to
          see my doctor" [syn: {doc}, {physician}, {MD}, {Dr.}, {medico}]
     2: (Roman Catholic Church) a title conferred on 33 saints who
        distinguished themselves through the othodoxy of their
        theological teaching; "the Doctors of the Church greatly
        influenced Christian thought down to the late Middle Ages"
        [syn: {Doctor of the Church}]
     3: children take the roles of doctor or patient or nurse and
        pretend they are at the doctor's office; "the children
        explored each other's bodies by playing the game of
        doctor"
     4: a person who holds Ph.D. degree from an academic
        institution; "she is a doctor of philosophy in physics"
        [syn: {Dr.}]

doctor
     v 1: alter and make impure, as with the intention to deceive;
          "Sophisticate rose water with geraniol" [syn: {sophisticate},
           {doctor up}]
     2: give medical treatment to
     3: restore by replacing a part or putting together what is torn
        or broken; "She repaired her TV set"; "Repair my shoes
        please" [syn: {repair}, {mend}, {fix}, {bushel}, {furbish
        up}, {restore}, {touch on}] [ant: {break}]