The Collaborative International Dictionary of English v.0.48:

Eutychian \Eu*tych"i*an\, n. (Eccl. Hist.)
   A follower of Eutyches [5th century], who held that the
   divine and the human in the person of Christ were blended
   together as to constitute but one nature; a monophysite; --
   opposed to Nestorian.
   [1913 Webster]