The Collaborative International Dictionary of English v.0.48:

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.
   [1913 Webster]

   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.
         [1913 Webster]

WordNet (r) 3.0 (2006):

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, punctuation mark]
    3: the use of certain marks to clarify meaning of written
       material by grouping words grammatically into sentences and
       clauses and phrases

Moby Thesaurus II by Grady Ward, 1.0:

36 Moby Thesaurus words for "punctuation":
   alphabet, ampersand, angle brackets, apostrophe, braces, colon,
   comma, dash, decimal point, diacritical mark, diagonal, dot,
   ellipsis, end stop, exclamation mark, full stop, hyphen, letter,
   parens, parentheses, period, point, punctuation marks,
   question mark, quotation marks, quotes, reference, reference mark,
   semicolon, single quotes, solidus, stop, tittle, virgule,
   writing system, written character



Bouvier's Law Dictionary, Revised 6th Ed (1856):

PUNCTUATION, construction. The act or method of placing points (q.v.) in a
written or printed instrument.
     2. By the word point is here understood all the points in grammar, as
the comma, the semicolon, the colon, and the like.
     3. All such instruments are to be construed without any regard to the
punctuation; and in a case of doubt, they ought to be construed in such a
manner that they may have some effect, rather than in one in which they
would be nugatory. Vide Toull. liv. 3, t. 2, c. 5, n. 430; 4 T. R. 65;
Barringt. on the Stat. 394, n. Vide article Points.