Source : Webster's Revised Unabridged Dictionary (1913)

Prolong \Pro*long"\, v. t. [imp. & p. p. {Prolonged}; p. pr. &
   vb. n. {Prolonging}.] [F. prolonger, L. prolongare; pro
   before, forth + longus long. See {Long}, a., and cf.
   {Prolongate}, {Purloin}. ]
   1. To extend in space or length; as, to prolong a line.

   2. To lengthen in time; to extend the duration of; to draw
      out; to continue; as, to prolong one's days.

            Prolong awhile the traitor's life.    --Shak.

            The unhappy queen with talk prolonged the night.
                                                  --Dryden.

   3. To put off to a distant time; to postpone. --Shak.

Source : WordNet®

prolong
     v 1: lengthen in time; cause to be or last longer; "We prolonged
          our stay"; "She extended her visit by another day"; "The
          meeting was drawn out until midnight" [syn: {protract},
          {extend}, {draw out}]
     2: lengthen or extend in duration or space; "We sustained the
        diplomatic negociations as long as possible"; "prolong the
        treatment of the patient"; "keep up the good work" [syn: {sustain},
         {keep up}]