Eutyches, a Byzantine heresiarch, who, in combating Nestorianism (q.v.), fell into the opposite extreme, and maintained that in the incarnation the human nature of Christ was absorbed in the divine, a doctrine which was condemned by the Council of Chalcedon in 448 (378‒454).
Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)
Eutropius, Flavius * Eutychianism