Source : Webster's Revised Unabridged Dictionary (1913)

Apply \Ap*ply"\, v. t. [imp. & p. p. {Applied}; p. pr. & vb. n.
   {Applying}.] [OF. aplier, F. appliquer, fr. L. applicare to
   join, fix, or attach to; ad + plicare to fold, to twist
   together. See {Applicant}, {Ply}.]
   1. To lay or place; to put or adjust (one thing to another);
      -- with to; as, to apply the hand to the breast; to apply
      medicaments to a diseased part of the body.

            He said, and the sword his throat applied. --Dryden.

   2. To put to use; to use or employ for a particular purpose,
      or in a particular case; to appropriate; to devote; as, to
      apply money to the payment of a debt.

   3. To make use of, declare, or pronounce, as suitable,
      fitting, or relative; as, to apply the testimony to the
      case; to apply an epithet to a person.

            Yet God at last To Satan, first in sin, his doom
            applied.                              --Milton.

   4. To fix closely; to engage and employ diligently, or with
      attention; to attach; to incline.

            Apply thine heart unto instruction.   --Prov. xxiii.
                                                  12.

   5. To direct or address. [R.]

            Sacred vows . . . applied to grisly Pluto. --Pope.

   6. To betake; to address; to refer; -- used reflexively.

            I applied myself to him for help.     --Johnson.

   7. To busy; to keep at work; to ply. [Obs.]

            She was skillful in applying his ``humors.'' --Sir
                                                  P. Sidney.

   8. To visit. [Obs.]

            And he applied each place so fast.    --Chapman.

   {Applied chemistry}. See under {Chemistry}.

   {Applied mathematics}. See under {Mathematics}.

Source : WordNet®

applied mathematics
     n : the branches of mathematics that are involved in the study
         of the physical or biological or sociological world [syn:
          {applied math}]