Monophysitism (/məˈnɒfᵻsaɪtᵻzəm/ or /məˈnɒfᵻsɪtᵻzəm/; Greek: μονοφυσιτισμός; Late Koine Greek [monofysitzˈmos] from μόνος monos, "only, single" and φύσις physis, "nature") is the Christological position that, after the union of the divine and the human in the historical Incarnation, Jesus Christ, as the incarnation of the eternal Son or Word (Logos) of God, had only a single "nature" which was either divine or a synthesis of divine and human. Monophysitism is contrasted to dyophysitism (or dia-, dio-, or duophysitism) which maintains that Christ maintained two natures, one divine and one human, after the Incarnation.
Historically, Monophysitism (usually capitalized in this sense) refers primarily to the position of those (especially in Egypt and to a lesser extent Syria) who rejected the Council of Chalcedon (the fourth ecumenical [worldwide] council), in 451. The moderate members of this group, however, maintained a "Miaphysite" theology that became that of the Oriental Orthodox churches. Many Oriental Orthodox reject the label "Monophysite" even as a generic term, but it is extensively used in the historical literature.