The Collaborative International Dictionary of English v.0.48:

Kingdom \King"dom\, n. [AS. cyningd[=o]m. See 2d King, and
   -dom.]
   1. The rank, quality, state, or attributes of a king; royal
      authority; sovereign power; rule; dominion; monarchy.
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            Thy kingdom is an everlasting kingdom. --Ps. cxiv.
                                                  13.
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            When Jehoram was risen up to the kingdom of his
            father, he strengthened himself.      --2 Chron.
                                                  xxi. 4.
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   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.
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            Unto the kingdom of perpetual night.  --Shak.
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            You're welcome,
            Most learned reverend sir, into our kingdom. --Shak.
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   3. An extensive scientific division distinguished by leading
      or ruling characteristics; a principal division; a
      department; as, the mineral kingdom. In modern biology,
      the division of life into five kingdoms is widely used for
      classification. "The animal and vegetable kingdoms."
                                                  --Locke.
      [1913 Webster +PJC]

   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.
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The Collaborative International Dictionary of English v.0.48:

Animal \An"i*mal\, a. [Cf. F. animal.]
   1. Of or relating to animals; as, animal functions.
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   2. Pertaining to the merely sentient part of a creature, as
      distinguished from the intellectual, rational, or
      spiritual part; as, the animal passions or appetites.
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   3. Consisting of the flesh of animals; as, animal food.
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   Animal magnetism. See Magnetism and Mesmerism.

   Animal electricity, the electricity developed in some
      animals, as the electric eel, torpedo, etc.

   Animal flower (Zool.), a name given to certain marine
      animals resembling a flower, as any species of actinia or
      sea anemone, and other Anthozoa, hydroids, starfishes,
      etc.

   Animal heat (Physiol.), the heat generated in the body of a
      living animal, by means of which the animal is kept at
      nearly a uniform temperature.

   Animal spirits. See under Spirit.

   Animal kingdom, the whole class of beings endowed with
      animal life. It embraces several subkingdoms, and under
      these there are Classes, Orders, Families, Genera,
      Species, and sometimes intermediate groupings, all in
      regular subordination, but variously arranged by different
      writers.

   Note: The following are the grand divisions, or subkingdoms,
         and the principal classes under them, generally
         recognized at the present time:
         Vertebrata, including Mammalia or Mammals, Aves or
         Birds, Reptilia, Amphibia, Pisces or Fishes,
         Marsipobranchiata (Craniota); and Leptocardia
         (Acrania). Tunicata, including the Thaliacea, and
         Ascidioidea or Ascidians. Articulata or Annulosa,
         including Insecta, Myriapoda, Malacapoda, Arachnida,
         Pycnogonida, Merostomata, Crustacea (Arthropoda); and
         Annelida, Gehyrea (Anarthropoda).
         Helminthes or Vermes, including Rotifera,
         Ch[ae]tognatha, Nematoidea, Acanthocephala, Nemertina,
         Turbellaria, Trematoda, Cestoidea, Mesozea.

WordNet (r) 3.0 (2006):

animal kingdom
    n 1: taxonomic kingdom comprising all living or extinct animals
         [syn: Animalia, kingdom Animalia, animal kingdom]

Moby Thesaurus II by Grady Ward, 1.0:

62 Moby Thesaurus words for "animal kingdom":
   Animalia, and fish, animal life, animality, beasts,
   beasts of field, beasts of prey, big game, birds, blood, breed,
   brood, brute creation, cattle, chain of being, clan, class,
   class structure, deme, domain, domestic animals, establishment,
   family, fauna, folk, furry creatures, game, gens, hierarchy, house,
   kind, kingdom, line, lineage, livestock, matriclan,
   mineral kingdom, nation, natural hierarchy, order, patriclan,
   pecking order, people, phratry, phyle, plant kingdom,
   power structure, pyramid, race, realm, sept, small game, species,
   stem, stirps, stock, strain, totem, tribe, vegetable kingdom,
   wild animals, wildlife