Source : Webster's Revised Unabridged Dictionary (1913)

Obiter \Ob"i*ter\, adv. [L., on the way; ob (see {Ob-}) + iter a
   going, a walk, way.]
   In passing; incidentally; by the way.

   {Obiter dictum} (Law), an incidental and collateral opinion
      uttered by a judge. See {Dictum}, n., 2
   (a) .

Source : WordNet®

obiter dictum
     n 1: an incidental remark [syn: {passing comment}]
     2: an opinion voiced by a judge on a point of law not directly
        bearing on the case in question and therefore not binding
        [syn: {dictum}]