Source : Webster's Revised Unabridged Dictionary (1913)

Ruling \Rul"ing\, a.
   1. Predominant; chief; reigning; controlling; as, a ruling
      passion; a ruling sovereign.

   2. Used in marking or engraving lines; as, a ruling machine
      or pen.

   Syn: Predominant; chief; controlling; directing; guiding;
        governing; prevailing; prevalent.

Ruling \Rul"ing\, n.
   1. The act of one who rules; ruled lines.

   2. (Law) A decision or rule of a judge or a court, especially
      an oral decision, as in excluding evidence.

Rule \Rule\, v. t. [imp. & p. p. {Ruled}; p. pr. & vb. n.
   {Ruling}.] [Cf. OF. riuler, ruiler, L. regulare. See {Rule},
   n., and cf. {Regulate}.]
   1. To control the will and actions of; to exercise authority
      or dominion over; to govern; to manage. --Chaucer.

            A bishop then must be blameless; . . . one that
            ruleth well his own house, having his children in
            subjection.                           --1 Tim. iii.
                                                  2, 4.

   2. To control or direct by influence, counsel, or persuasion;
      to guide; -- used chiefly in the passive.

            I think she will be ruled In all respects by me.
                                                  --Shak.

   3. To establish or settle by, or as by, a rule; to fix by
      universal or general consent, or by common practice.

            That's are ruled case with the schoolmen.
                                                  --Atterbury.

   4. (Law) To require or command by rule; to give as a
      direction or order of court.

   5. To mark with lines made with a pen, pencil, etc., guided
      by a rule or ruler; to print or mark with lines by means
      of a rule or other contrivance effecting a similar result;
      as, to rule a sheet of paper of a blank book.

   {Ruled surface} (Geom.), any surface that may be described by
      a straight line moving according to a given law; -- called
      also a {scroll}.



   {Bow pen}. See {Bow-pen}.

   {Dotting pen}, a pen for drawing dotted lines.

   {Drawing}, or {Ruling}, {pen}, a pen for ruling lines having
      a pair of blades between which the ink is contained.

   {Fountain pen}, {Geometric pen}. See under {Fountain}, and
      {Geometric}.

   {Music pen}, a pen having five points for drawing the five
      lines of the staff.

   {Pen and ink}, or {pen-and-ink}, executed or done with a pen
      and ink; as, a pen and ink sketch.

   {Pen feather}. A pin feather. [Obs.]

   {Pen name}. See under {Name}.

   {Sea pen} (Zo["o]l.), a pennatula. [Usually written
      {sea-pen}.]

Source : WordNet®

ruling
     adj : exercising power or authority [syn: {regnant}, {reigning}]

ruling
     n : the reason for a court's judgment (as opposed to the
         decision itself) [syn: {opinion}]