Source : Webster's Revised Unabridged Dictionary (1913)

Epideictic \Ep`i*deic"tic\, a. [Gr. ?, fr. ? to show forth,
   display; 'epi` + ? to show. Cf. {Epidictic}.]
   Serving to show forth, explain, or exhibit; -- applied by the
   Greeks to a kind of oratory, which, by full amplification,
   seeks to persuade.