Source : Webster's Revised Unabridged Dictionary (1913)

Kingdom \King"dom\, n. [AS. cyningd?m. See 2d {King}, and
   -{dom}.]
   1. The rank, quality, state, or attributes of a king; royal
      authority; sovereign power; rule; dominion; monarchy.

            Thy kingdom is an everlasting kingdom. --Ps. cxiv.
                                                  13.

            When Jehoram was risen up to the kingdom of his
            father, he strengthened himself.      --2 Chron.
                                                  xxi. 4.

   2. The territory or country subject to a king or queen; the
      dominion of a monarch; the sphere in which one is king or
      has control.

            Unto the kingdom of perpetual night.  --Shak.

            You're welcome, Most learned reverend sir, into our
            kingdom.                              --Shak.

   3. An extensive scientific division distinguished by leading
      or ruling characteristics; a principal division; a
      department; as, the mineral kingdom. ``The animal and
      vegetable kingdoms.''                       --Locke.

   {Animal kingdom}. See under {Animal}.

   {Kingdom of God}.
      (a) The universe.
      (b) That spiritual realm of which God is the acknowledged
          sovereign.
      (c) The authority or dominion of God.

   {Mineral kingdom}. See under {Mineral}.

   {United Kingdom}. See under {United}.

   {Vegetable kingdom}. See under {Vegetable}.

   Syn: Realm; empire; dominion; monarchy; sovereignty; domain.

Source : WordNet®

kingdom
     n 1: a domain in which something is dominant; "the untroubled
          kingdom of reason"; "a land of make-believe"; "the rise
          of the realm of cotton in the south" [syn: {land}, {realm}]
     2: a country with a king as head of state
     3: the domain ruled by a king or queen [syn: {realm}]
     4: a monarchy with a king or queen as head of state
     5: one of seven biological categories: Monera or Protoctista or
        Plantae or Fungi or Animalia
     6: a basic group of natural objects