The Collaborative International Dictionary of English v.0.48:

Deplete \De*plete"\, v. t. [imp. & p. p. Depleted; p. pr. &
   vb. n. Depleting.] [From L. deplere to empty out; de- +
   plere to fill. Forined like replete, complete. See Fill,
   Full, a.]
   1. (Med.) To empty or unload, as the vessels of human system,
      by bloodletting or by medicine. --Copland.
      [1913 Webster]

   2. To reduce by destroying or consuming the vital powers of;
      to exhaust, as a country of its strength or resources, a
      treasury of money, etc. --Saturday Review.
      [1913 Webster]

WordNet (r) 3.0 (2006):

deplete
    v 1: use up (resources or materials); "this car consumes a lot
         of gas"; "We exhausted our savings"; "They run through 20
         bottles of wine a week" [syn: consume, eat up, use
         up, eat, deplete, exhaust, run through, wipe
         out]