el·o·quence/ˈeləkwəns/

Noun:	Fluent or persuasive speaking or writing. The art or manner of such speech or writing.
	Synonyms: expression, rhetoric, articulation, diction, expressiveness, oration

http://en.wikipedia.org/wiki/Eloquence

Eloquence (from Latin eloquentia) is fluent, forcible, elegant or persuasive speaking. It is primarily the power of expressing strong emotions in striking and appropriate language, thereby producing conviction or persuasion. The term is also used for writing in a fluent style.

The concept of eloquence dates to the ancient Greeks, Calliope,(one of the nine daughters of Zeus and Mnemosyne) being the Muse of epic poetry and eloquence.

Too bad Callie Torres from Grey’s Anatomy, whom is also named Calliope, isn’t as eloquent as her namesake.

I personally think Eloquence is about expressing complex emotions and conveying them so well that the whole audience knows exactly what you meant to the point of resonance.