The Collaborative International Dictionary of English v.0.48:

Currency \Cur"ren*cy\ (k?r"r?n-c?), n.; pl. Currencies (-s?z).
   [Cf. LL. currentia a current, fr. L. currens, p. pr. of
   currere to run. See Current.]
   1. A continued or uninterrupted course or flow like that of a
      stream; as, the currency of time. [Obs.] --Ayliffe.
      [1913 Webster]

   2. The state or quality of being current; general acceptance
      or reception; a passing from person to person, or from
      hand to hand; circulation; as, a report has had a long or
      general currency; the currency of bank notes.
      [1913 Webster]

   3. That which is in circulation, or is given and taken as
      having or representing value; as, the currency of a
      country; a specie currency; esp., government or bank notes
      circulating as a substitute for metallic money.
      [1913 Webster]

   4. Fluency; readiness of utterance. [Obs.]
      [1913 Webster]

   5. Current value; general estimation; the rate at which
      anything is generally valued.
      [1913 Webster]

            He . . . takes greatness of kingdoms according to
            their bulk and currency, and not after intrinsic
            value.                                --Bacon.
      [1913 Webster]

            The bare name of Englishman . . . too often gave a
            transient currency to the worthless and ungrateful.
                                                  --W. Irving.
      [1913 Webster]

WordNet (r) 3.0 (2006):

currency
    n 1: the metal or paper medium of exchange that is presently
         used
    2: general acceptance or use; "the currency of ideas"
    3: the property of belonging to the present time; "the currency
       of a slang term" [syn: currentness, currency, up-to-
       dateness]

Moby Thesaurus II by Grady Ward, 1.0:

95 Moby Thesaurus words for "currency":
   PR, and pence, averageness, ballyhoo, blurb, bon ton, bright light,
   cash, celebrity, circulating medium, coin, coinage, coined liberty,
   cold cash, common knowledge, commonality, commonness,
   commonplaceness, cry, daylight, dollars, dough, eclat,
   emergency money, exposure, extensiveness, fame, famousness,
   fashionableness, filthy lucre, fractional currency, generality,
   glare, gold, habitualness, hard cash, hard currency, hoopla,
   hue and cry, legal tender, lettuce, limelight, lucre, mammon,
   managed currency, maximum dissemination, medium of exchange,
   mintage, modishness, money, necessity money, needful, normality,
   notoriety, ordinariness, pelf, plug, popularity, postage currency,
   postal currency, pounds, press notice, prevalence, public eye,
   public knowledge, public relations, public report, publicity,
   publicity story, publicness, puff, rampantness, reclame, reign,
   report, rifeness, routineness, run, scrip, shillings, silver,
   soft currency, specie, spotlight, standardness, sterling,
   stylishness, sweepingness, the almighty dollar, the wherewith,
   the wherewithal, usualness, voguishness, widespreadness,
   write-up



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

CURRENCY. The money which passes, at a fixed value, from hand to hand; money
which is authorized by law.
     2. By art. 1, s. 8, the Constitution of the United States authorizes
congress "to coin money, and to regulate the value thereof." Changes in the
currency ought not to be made but for the most urgent reason, as they
unsettle commerce, both at home and abroad. Suppose Peter contracts to pay
Paul one thousand dollars in six months-the dollar of a certain fineness
of silver, weighing one hundred and twelve and a half grains-and
afterwards, before the money becomes due, the value of the dollar is
changed, and it weighs now but fifty-six and a quarter grains; will one
thousand of the new dollars pay the old debt? Different opinion may be
entertained, but it seems that such payment would be complete; because, 1.
The creditor is bound to receive the public currency; and, 2. He is bound to
receive it at its legal value. 6 Duverg. n. 174.