Rhetoric

Rhetoric, the science or art of persuasive or effective speech, written as well as spoken, and that both in theory and practice was cultivated to great perfection among the ancient Greeks and Romans, and to some extent in the Middle Ages and later, but is much less cultivated either as a science or an art to-day.

Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)