Source : Webster's Revised Unabridged Dictionary (1913)

Diction \Dic"tion\, n. [L. dicto a saying, a word, fr. dicere,
   dictum, to say; akin to dicare to proclaim, and to E. teach,
   token: cf. F. diction. See {Teach}, and cf. {Benison},
   {Dedicate}, {Index}, {Judge}, {Preach}, {Vengeance}.]
   Choice of words for the expression of ideas; the
   construction, disposition, and application of words in
   discourse, with regard to clearness, accuracy, variety, etc.;
   mode of expression; language; as, the diction of Chaucer's
   poems.

         His diction blazes up into a sudden explosion of
         prophetic grandeur.                      --De Quincey.

   Syn: {Diction}, {Style}, {Phraseology}.

   Usage: Style relates both to language and thought; diction,
          to language only; phraseology, to the mechanical
          structure of sentences, or the mode in which they are
          phrased. The style of Burke was enriched with all the
          higher graces of composition; his diction was varied
          and copious; his phraseology, at times, was careless
          and cumbersome. ``Diction is a general term applicable
          alike to a single sentence or a connected composition.
          Errors in grammar, false construction, a confused
          disposition of words, or an improper application of
          them, constitute bad diction; but the niceties, the
          elegancies, the peculiarities, and the beauties of
          composition, which mark the genius and talent of the
          writer, are what is comprehended under the name of
          style.'' --Crabb.

Source : WordNet®

diction
     n 1: the articulation of speech regarded from the point of view
          of its intelligibility to the audience [syn: {enunciation}]
     2: the manner in which something is expressed in words; "use
        concise military verbiage"- G.S.Patton [syn: {wording}, {phrasing},
         {phraseology}, {choice of words}, {verbiage}]