noun (n)

• a punctuation mark (,) used to indicate the separation of elements within the grammatical structure of a sentence(noun.communication)

  source: wordnet30
• anglewing butterfly with a comma-shaped mark on the underside of each hind wing(noun.animal)

  Synonym:
  comma butterfly, polygonia comma
  

  source: wordnet30
• A character or point [,] marking the smallest divisions of a sentence, written or printed.(noun)

  source: webster1913