Source : Webster's Revised Unabridged Dictionary (1913)

Ponder \Pon"der\, v. t. [imp. & p. p. {Pondered}; p. pr. & vb.
   n. {Pondering}.] [L. ponderare, fr. pondus, ponderis, a
   weight, fr. pendere to weigh: cf. F. pond['e]rer. See
   {Pendant}, and cf. {Pound} a weight.]
   1. To weigh. [Obs.]

   2. To weigh in the mind; to view with deliberation; to
      examine carefully; to consider attentively.

            Ponder the path of thy feet.          --Prov. iv.
                                                  26.

   Syn: To {Ponder}, {Consider}, {Muse}.

   Usage: To consider means to view or contemplate with fixed
          thought. To ponder is to dwell upon with long and
          anxious attention, with a view to some practical
          result or decision. To muse is simply to think upon
          continuously with no definite object, or for the
          pleasure it gives. We consider any subject which is
          fairly brought before us; we ponder a concern
          involving great interests; we muse on the events of
          childhood.

Ponder \Pon"der\, v. i.
   To think; to deliberate; to muse; -- usually followed by on
   or over. --Longfellow.

Source : WordNet®

ponder
     v : reflect deeply on a subject; "I mulled over the events of
         the afternoon"; "philosophers have speculated on the
         question of God for thousands of years"; "The scientist
         must stop to observe and start to excogitate" [syn: {chew
         over}, {think over}, {meditate}, {excogitate}, {contemplate},
          {muse}, {reflect}, {mull}, {mull over}, {ruminate}, {speculate}]

Source : Free On-Line Dictionary of Computing

Ponder
     
        A {non-strict} {polymorphic}, {functional language} by Jon
        Fairbairn .
     
        Ponder's type system is unusual.  It is more powerful than the
        {Hindley-Milner type} system used by {ML} and {Miranda} and
        extended by {Haskell}.  Ponder adds extra recursive 'mu' types
        to those of Girard's {System F}, allowing more general
        {recursion}.  Surprisingly, the type system and {type
        inference} {algorithm} are still not completely understood.
     
        ["Ponder and its Type System", J. Fairbairn, TR 31, Cambridge
        U Computer Lab, Nov 1982].
     
        [J. Fairbairn, "Design and Implementation of a Simple Typed
        Language based on the Lambda-Calculus", Technical Report
        No. 75, Computer Laboratory, University of Cambridge, May
        1985].
     
        [J. Fairbairn, "A New Type-Checker for a Functional Language",
        Technical Report No. 53, Computer Laboratory, University of
        Cambridge, 1984].
     
        [J. Fairbairn, "Some Types with Inclusion Properties in
        \forall, \rightarrow, \mu", Technical Report No. 171, Computer
        Laboratory, University of Cambridge, Jun 1989].
     
        [Valeria C. V. de Paiva, "Subtyping in Ponder (Preliminary
        Report)", Technical Report No. 203, Computer Laboratory,
        University of Cambridge, Aug 1990].