Hypostatic Union

The doctrine of the substantial union of the divine and human natures in the one person (hypostasis) of Jesus Christ, formulated by Cyril of Alexandria* in opposition to Nestorius. He described the union as “natural” (kata physin) or “hypostatic” (kath' hypostasin). The doctrine was formally accepted at the Council of Chalcedon (451), though the phrase “hypostatic union” was not used, in the words “the property of each nature being preserved and coalescing in one `prosopon' and `hypostasis.' “

See Incarnation.