An adherent of Nestorius, patriarch of Constantinople to the fifth century, who has condemned as a heretic for maintaining that the divine and the human natures were not merged into one nature in Christ (who was God in man), and, hence, that it was improper to call Mary the mother of Christ; also, one of the sect established by the followers of Nestorius in Persia, india, and other Oriental countries, and still in existence. opposed to Eutychian.