The Collaborative International Dictionary of English v.0.48:

Prudence \Pru"dence\, n. [F., fr. L. prudentia, contr. from
   providentia. See Prudent, and cf. Providence.]
   The quality or state of being prudent; wisdom in the way of
   caution and provision; discretion; carefulness; hence, also,
   economy; frugality.
   [1913 Webster]

         Prudence is principally in reference to actions to be
         done, and due means, order, seasons, and method of
         doing or not doing.                      --Sir M. Hale.
   [1913 Webster]

         Prudence supposes the value of the end to be assumed,
         and refers only to the adaptation of the means. It is
         the relation of right means for given ends. --Whewell.
   [1913 Webster]

   Syn: Wisdom; forecast; providence; considerateness;
        judiciousness; discretion; caution; circumspection;
        judgment. See Wisdom.
        [1913 Webster]

WordNet (r) 3.0 (2006):

prudence
    n 1: discretion in practical affairs [ant: imprudence]
    2: knowing how to avoid embarrassment or distress; "the servants
       showed great tact and discretion" [syn: discretion,
       discreetness, circumspection, prudence]