The Collaborative International Dictionary of English v.0.48:



   3. Importance, significance, dignity, etc; hence,
      seriousness; enormity; as, the gravity of an offense.
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            They derive an importance from . . . the gravity of
            the place where they were uttered.    --Burke.
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   4. (Physics) The tendency of a mass of matter toward a center
      of attraction; esp., the tendency of a body toward the
      center of the earth; terrestrial gravitation.
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   5. (Mus.) Lowness of tone; -- opposed to acuteness.
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   Center of gravity See under Center.

   Gravity battery, See Battery, n., 4.

   Specific gravity, the ratio of the weight of a body to the
      weight of an equal volume of some other body taken as the
      standard or unit. This standard is usually water for
      solids and liquids, and air for gases. Thus, 19, the
      specific gravity of gold, expresses the fact that, bulk
      for bulk, gold is nineteen times as heavy as water.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

specific \spe*cif"ic\ (sp[-e]*s[i^]f"[i^]k), a. [F.
   sp['e]cifique, or NL. spesificus; L. species a particular
   sort or kind + facere to make. Cf. specify.]
   1. Of or pertaining to a species; characterizing or
      constituting a species; possessing the peculiar property
      or properties of a thing which constitute its species, and
      distinguish it from other things; as, the specific form of
      an animal or a plant; the specific qualities of a drug;
      the specific distinction between virtue and vice.
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            Specific difference is that primary attribute which
            distinguishes each species from one another. --I.
                                                  Watts.
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   2. Specifying; definite, or making definite; limited;
      precise; discriminating; as, a specific statement.
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   3. (Med.) Exerting a peculiar influence over any part of the
      body; preventing or curing disease by a peculiar
      adaptation, and not on general principles; as, quinine is
      a specific medicine in cases of malaria.
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            In fact, all medicines will be found specific in the
            perfection of the science.            --Coleridge.
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   Specific character (Nat. Hist.), a characteristic or
      characteristics distinguishing one species from every
      other species of the same genus.

   Specific disease (Med.)
      (a) A disease which produces a determinate definite effect
          upon the blood and tissues or upon some special
          tissue.
      (b) A disease which is itself uniformly produced by a
          definite and peculiar poison or organism.

   Specific duty. (Com.) See under Duty.

   Specific gravity. (Physics) See under Gravity.

   Specific heat (Physics), the quantity of heat required to
      raise the temperature of a body one degree, taking as the
      unit of measure the quantity required to raise the same
      weight of water from zero to one degree; thus, the
      specific heat of mercury is 0.033, that of water being
      1.000.

   Specific inductive capacity (Physics), the effect of a
      dielectric body in producing static electric induction as
      compared with that of some other body or bodies referred
      to as a standard.

   Specific legacy (Law), a bequest of a particular thing, as
      of a particular animal or piece of furniture, specified
      and distinguished from all others. --Wharton. --Burrill.

   Specific name (Nat. Hist.), the name which, appended to the
      name of the genus, constitutes the distinctive name of the
      species; -- originally applied by Linnaeus to the
      essential character of the species, or the essential
      difference. The present specific name he at first called
      the trivial name.

   Specific performance (Law), the peformance of a contract or
      agreement as decreed by a court of equity.
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WordNet (r) 3.0 (2006):

specific gravity
    n 1: the density of a substance relative to the density of water

Moby Thesaurus II by Grady Ward, 1.0:

33 Moby Thesaurus words for "specific gravity":
   G, G suit, apogeotropism, closeness, compactness, congestedness,
   congestion, consistence, consistency, crowdedness, denseness,
   density, firmness, geotropism, gluiness, gravitation, graviton,
   gravity, hardness, impenetrability, impermeability, imporosity,
   incompressibility, jammedness, mass, relative density, solidity,
   solidness, spissitude, thickness, viscidity, viscosity,
   viscousness