Source : Webster's Revised Unabridged Dictionary (1913)

Punctuation \Punc`tu*a"tion\, n. [Cf. F. ponctuation.] (Gram.)
   The act or art of punctuating or pointing a writing or
   discourse; the art or mode of dividing literary composition
   into sentences, and members of a sentence, by means of
   points, so as to elucidate the author's meaning.

   Note: Punctuation, as the term is usually understood, is
         chiefly performed with four points: the period [.], the
         colon [:], the semicolon [;], and the comma [,]. Other
         points used in writing and printing, partly rhetorical
         and partly grammatical, are the note of interrogation
         [?], the note of exclamation [!], the parentheses [()],
         the dash [--], and brackets []. It was not until the
         16th century that an approach was made to the present
         system of punctuation by the Manutii of Venice. With
         Caxton, oblique strokes took the place of commas and
         periods.

Source : WordNet®

punctuation
     n 1: something that makes repeated and regular interruptions or
          divisions
     2: the marks used to clarify meaning by indicating separation
        of words into sentences and clauses and phrases [syn: {punctuation
        mark}]
     3: the use of certain marks to clarify meaning of written
        material by grouping words grammatically into sentences
        and clauses and phrases