The DICT Development Group

  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.
        [1913 Webster]
  
     2. (Mus.) A small interval (the difference between a major
        and minor half step), seldom used except by tuners.
        [1913 Webster]
  
     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 (Zool.), an American butterfly ({Grapta
        comma), having a white comma-shaped marking on the under
        side of the wings.
        [1913 Webster]

  comma bacillus
      n 1: comma-shaped bacteria that cause Asiatic cholera [syn:
           comma bacillus, Vibrio comma]