What is "theotokos"

Theotokos (; ; ) is a title of Mary, mother of Jesus, used especially in Eastern Christianity. Its literal English translations include "God-bearer", "Birth-Giver of God", and "the one who gives birth to God." Looser translations include the primarily Catholic title "Mother of God" .

The ancient use of this term is emphasized in churches of the Syriac tradition, which have been using this title in their ancient liturgies for centuries; e.g., the Liturgy of Mari and Addai (3rd century) and the Liturgy of St James (4th century). The Council of Ephesus decreed in 431 that Mary is the Theotokos because her son Jesus is both God and man: one divine person with two natures (divine and human) intimately and hypostatically united.

Roman Catholics and Anglicans use the title Mother of God more often than Theotokos. Lutherans also venerate and honor Mary as Mother of God as expressed by its founder, Martin Luther; the title was officially confessed in their Formula of Concord, accepted by Lutheran World Federation.