Comma

n.
  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.
    3. 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 (Zoöl.),
    an American butterfly (Grapta comma), having a white comma-shaped marking on the under side of the wings.