The Collaborative International Dictionary of English v.0.48:

Balance \Bal"ance\ (b[a^]l"ans), n. [OE. balaunce, F. balance,
   fr. L. bilanx, bilancis, having two scales; bis twice (akin
   to E. two) + lanx plate, scale.]
   1. An apparatus for weighing.
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   Note: In its simplest form, a balance consists of a beam or
         lever supported exactly in the middle, having two
         scales or basins of equal weight suspended from its
         extremities. Another form is that of the Roman balance,
         our steelyard, consisting of a lever or beam, suspended
         near one of its extremities, on the longer arm of which
         a counterpoise slides. The name is also given to other
         forms of apparatus for weighing bodies, as to the
         combinations of levers making up platform scales; and
         even to devices for weighing by the elasticity of a
         spring.
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   2. Act of weighing mentally; comparison; estimate.
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            A fair balance of the advantages on either side.
                                                  --Atterbury.
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   3. Equipoise between the weights in opposite scales.
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   4. The state of being in equipoise; equilibrium; even
      adjustment; steadiness.
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            And hung a bottle on each side
            To make his balance true.             --Cowper.
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            The order and balance of the country were destroyed.
                                                  --Buckle.
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            English workmen completely lose their balance. --J.
                                                  S. Mill.
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   5. An equality between the sums total of the two sides of an
      account; as, to bring one's accounts to a balance; --
      also, the excess on either side; as, the balance of an
      account. "A balance at the banker's." --Thackeray.
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            I still think the balance of probabilities leans
            towards the account given in the text. --J. Peile.
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   6. (Horol.) A balance wheel, as of a watch, or clock. See
      Balance wheel (in the Vocabulary).
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   7. (Astron.)
      (a) The constellation Libra.
      (b) The seventh sign in the Zodiac, called Libra, which
          the sun enters at the equinox in September.
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   8. A movement in dancing. See Balance, v. t., 8.
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   Balance electrometer, a kind of balance, with a poised
      beam, which indicates, by weights suspended from one arm,
      the mutual attraction of oppositely electrified surfaces.
      --Knight.

   Balance fish. (Zool.) See Hammerhead.

   Balance knife, a carving or table knife the handle of which
      overbalances the blade, and so keeps it from contact with
      the table.

   Balance of power (Politics), such an adjustment of power
      among sovereign states that no one state is in a position
      to interfere with the independence of the others;
      international equilibrium; also, the ability (of a state
      or a third party within a state) to control the relations
      between sovereign states or between dominant parties in a
      state.

   Balance sheet (Bookkeeping), a paper showing the balances
      of the open accounts of a business, the debit and credit
      balances footing up equally, if the system of accounts be
      complete and the balances correctly taken.

   Balance thermometer, a thermometer mounted as a balance so
      that the movement of the mercurial column changes the
      inclination of the tube. With the aid of electrical or
      mechanical devices adapted to it, it is used for the
      automatic regulation of the temperature of rooms warmed
      artificially, and as a fire alarm.

   Balance of torsion. See Torsion Balance.

   Balance of trade (Pol. Econ.), an equilibrium between the
      money values of the exports and imports of a country; or
      more commonly, the amount required on one side or the
      other to make such an equilibrium.

   Balance valve, a valve whose surfaces are so arranged that
      the fluid pressure tending to seat, and that tending to
      unseat, the valve, are nearly in equilibrium; esp., a
      puppet valve which is made to operate easily by the
      admission of steam to both sides. See Puppet valve.

   Hydrostatic balance. See under Hydrostatic.

   To lay in balance, to put up as a pledge or security.
      [Obs.] --Chaucer.

   To strike a balance, to find out the difference between the
      debit and credit sides of an account.
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WordNet (r) 3.0 (2006):

balance of trade
    n 1: the difference in value over a period of time of a
         country's imports and exports of merchandise; "a nation's
         balance of trade is favorable when its exports exceed its
         imports" [syn: balance of trade, trade balance,
         visible balance, trade gap]

Moby Thesaurus II by Grady Ward, 1.0:

26 Moby Thesaurus words for "balance of trade":
   big business, business, business dealings, commerce,
   commercial affairs, commercial relations, dealing, dealings,
   fair trade, free trade, industry, intercourse, market, marketing,
   mercantile business, merchantry, multilateral trade,
   reciprocal trade, restraint of trade, small business,
   the business world, the marketplace, trade, traffic, truck,
   unilateral trade



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

BALANCE OF TRADE, Com. law. The difference between the exports and
importations, between two countries. The balance of trade is against that
country which has imported more than it has exported, for which it is debtor
to the other country.