The Collaborative International Dictionary of English v.0.48:

Eloquence \El"o*quence\, n. [F. ['e]loquence, L. eloquentia, fr.
   eloquens. See Eloquent.]
   1. Fluent, forcible, elegant, and persuasive speech in
      public; the power of expressing strong emotions in
      striking and appropriate language either spoken or
      written, thereby producing conviction or persuasion.
      [1913 Webster]

            Eloquence is speaking out . . . out of the abundance
            of the heart.                         --Hare.
      [1913 Webster]

   2. Fig.: Whatever produces the effect of moving and
      persuasive speech.
      [1913 Webster]

            Silence that spoke and eloquence of eyes. --Pope.
      [1913 Webster]

            The hearts of men are their books; events are their
            tutors; great actions are their eloquence.
                                                  --Macaulay.
      [1913 Webster]

   3. That which is eloquently uttered or written.
      [1913 Webster]

            O, let my books be then the eloquence
            And dumb presagers of my speaking breast. --Shak.

   Syn: Oratory; rhetoric.
        [1913 Webster]

WordNet (r) 3.0 (2006):

eloquence
    n 1: powerful and effective language; "his eloquence attracted a
         large congregation"; "fluency in spoken and written English
         is essential"; "his oily smoothness concealed his guilt
         from the police" [syn: eloquence, fluency,
         smoothness]

The Devil's Dictionary (1881-1906):

ELOQUENCE, n.  The art of orally persuading fools that white is the
color that it appears to be.  It includes the gift of making any color
appear white.