Source : Webster's Revised Unabridged Dictionary (1913)

Poetic \Po*et"ic\, Poetical \Po*et"ic*al\, a. [L. po["e]ticus,
   Gr. ?: cf. F. po['e]tiquee.]
   1. Of or pertaining to poetry; suitable for poetry, or for
      writing poetry; as, poetic talent, theme, work,
      sentiments. --Shak.

   2. Expressed in metrical form; exhibiting the imaginative or
      the rhythmical quality of poetry; as, a poetical
      composition; poetical prose.

   {Poetic license}. See {License}, n., 4.

Source : WordNet®

poetic license
     n : license used by a writer or artist to heighten the effect of
         their work