Source : Webster's Revised Unabridged Dictionary (1913)

Dissipation \Dis`si*pa"tion\, n. [L. dissipatio: cf. F.
   dissipation.]
   1. The act of dissipating or dispersing; a state of
      dispersion or separation; dispersion; waste.

            Without loss or dissipation of the matter. --Bacon.

            The famous dissipation of mankind.    --Sir M. Hale.

   2. A dissolute course of life, in which health, money, etc.,
      are squandered in pursuit of pleasure; profuseness in
      vicious indulgence, as late hours, riotous living, etc.;
      dissoluteness.

            To reclaim the spendthrift from his dissipation and
            extravagance.                         --P. Henry.

   3. A trifle which wastes time or distracts attention.

            Prevented from finishing them [the letters] a
            thousand avocations and dissipations. --Swift.

   {Dissipation of energy}. Same as {Degradation of energy},
      under {Degradation}.

Source : WordNet®

dissipation
     n 1: breaking up and scattering by dispersion; "the dissipation
          of the mist"
     2: dissolute indulgence in sensual pleasure [syn: {profligacy},
         {dissolution}, {licentiousness}]
     3: useless or profitless activity; using or expending or
        consuming thoughtlessly or carelessly; "if the effort
        brings no compensating gain it is a waste"; "mindless
        dissipation of natural resources" [syn: {waste}, {wastefulness}]