The Collaborative International Dictionary of English v.0.48:

Epichirema \Ep`i*chi*re"ma\, n.; pl. Epichiremata. [L., fr.
   Gr. ?, from ? to attempt to prove.] (Rhet. & Logic)
   A syllogism in which the proof of the major or minor premise,
   or both, is introduced with the premises themselves, and the
   conclusion is derived in the ordinary manner. [Written also
   epicheirema.]
   [1913 Webster]