The Collaborative International Dictionary of English v.0.48:

Commons \Com"mons\, n. pl.,
   1. The mass of the people, as distinguished from the titled
      classes or nobility; the commonalty; the common people.
      [Eng.]
      [1913 Webster]

            'T is like the commons, rude unpolished hinds,
            Could send such message to their sovereign. --Shak.
      [1913 Webster]

            The word commons in its present ordinary
            signification comprises all the people who are under
            the rank of peers.                    --Blackstone.
      [1913 Webster]

   2. The House of Commons, or lower house of the British
      Parliament, consisting of representatives elected by the
      qualified voters of counties, boroughs, and universities.
      [1913 Webster]

            It is agreed that the Commons were no part of the
            great council till some ages after the Conquest.
                                                  --Hume.
      [1913 Webster]

   3. Provisions; food; fare, -- as that provided at a common
      table in colleges and universities.
      [1913 Webster]

            Their commons, though but coarse, were nothing
            scant.                                --Dryden.
      [1913 Webster]

   4. A club or association for boarding at a common table, as
      in a college, the members sharing the expenses equally;
      as, to board in commons.
      [1913 Webster]

   5. A common; public pasture ground.
      [1913 Webster]

            To shake his ears, and graze in commons. --Shak.
      [1913 Webster]

   Doctors' Commons, a place near St. Paul's Churchyard in
      London where the doctors of civil law used to common
      together, and where were the ecclesiastical and admiralty
      courts and offices having jurisdiction of marriage
      licenses, divorces, registration of wills, etc.

   To be on short commons, to have a small allowance of food.
      [Colloq.]
      [1913 Webster] Common sense

The Collaborative International Dictionary of English v.0.48:

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; a learned man. [Obs.]
      [1913 Webster]

            One of the doctors of Italy, Nicholas Macciavel. --
                                                  Bacon.
      [1913 Webster]

   2. An academical title, originally meaning a man 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.
      [1913 Webster]

   3. One duly licensed to practice medicine; a member of the
      medical profession; a physician.
      [1913 Webster]

            By medicine life may be prolonged, yet death
            Will seize the doctor too.            -- Shak.
      [1913 Webster]

   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.
      [1913 Webster]

   5. (Zool.) The friar skate. [Prov. Eng.]
      [1913 Webster]

   Doctors' Commons. See under Commons.

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

   Doctor fish (Zool.), 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.
      [1913 Webster]

Bouvier's Law Dictionary, Revised 6th Ed (1856):

DOCTORS COMMONS. A building in London used for a college of civilians. Here
the judge of the court of arches, the judge of the admiralty, and the judge
of the court of Canterbury, with other eminent civilians, reside. Commons
signifies, in old English, pittance or allowance; because it is meant in
common among societies, as Universities, Inns of Courts, Doctors Commons,
&c. The Latin word is, demensum a demetiendo; dividing every one his part
Minsheu. It is called Doctors Commons, because the persons residing there
live in a collegiate commoning together.