Source : Webster's Revised Unabridged Dictionary (1913)

Comma \Com"ma\, n. [L. comma part of a sentence, comma, Gr. ?
   clause, fr. ? to cut off. Cf. {Capon}.]
   1. A character or point [,] marking the smallest divisions of
      a sentence, written or printed.

   2. (Mus.) A small interval (the difference between a major
      and minor half step), seldom used except by tuners.

   {Comma bacillus} (Physiol.), a variety of bacillus shaped
      like a comma, found in the intestines of patients
      suffering from cholera. It is considered by some as having
      a special relation to the disease; -- called also {cholera
      bacillus}.

   {Comma butterfly} (Zo["o]l.), an American butterfly ({Grapta
      comma}), having a white comma-shaped marking on the under
      side of the wings.

Source : WordNet®

comma
     n 1: a punctuation mark (,) used to indicate the separation of
          elements within the grammatical structure of a sentence
     2: anglewing butterfly with a comma-shaped mark on the
        underside of each hind wing [syn: {comma butterfly}, {Polygonia
        comma}]

Source : Free On-Line Dictionary of Computing

Comma
     
        COMputable MAthematics.
     
        An {ESPRIT} project at KU {Nijmegen}.
     
        (1994-11-30)

comma
     
         "," {ASCII} character 44.  Common names: {ITU-T}:
        comma.  Rare: {ITU-T}: cedilla; {INTERCAL}: tail.
     
        In the {C} programming language, "," is an operator which
        evaluates its first argument (which presumably has
        {side-effect}s) and then returns the value of its second
        argument.  This is useful in "for" statements and {macro}s.
     
        (1995-03-10)