Theotokos is a compound of two Greek words, Θεός God and τόκος parturition, childbirth. Literally, this translates as God-bearer or the one who gives birth to God; historian Jaroslav Pelikan translated it more precisely as “the one who gives birth to the one who is God”.[7] However, since many English-speaking Orthodox find this literal translation awkward, in liturgical use, Theotokos is often left untranslated, or paraphrased as Mother of God. The latter title is the literal translation of a distinct title in Greek, Μήτηρ του Θεού (translit. Mētēr tou Theou). Mother of God also accurately translates the Greek words Θεομήτωρ (translit. Theomētor; also spelled Θεομήτηρ, translit. Theomētēr) and Μητρόθεος (translit. Mētrotheos), which are found in patristic and liturgical texts, e.g.
… [80] περιφανῶς ἡ ἱερὰ θεομήτωρ ἐξετέλει … [109] ἐκφαντικώτατά σε τὴν θεοτόκον προσημαίνουσαν …[8]
The English term Mother of God is mostly used as an imprecise translation of Theotokos, and frequently requires explanation.[9] The other principal use of Mother of God has been as the precise and literal translation of Μήτηρ Θεού, a Greek term which has an established usage of its own in traditional Orthodox and Catholic theological writing, hymnography, and iconography. In an abbreviated form ΜΡ ΘΥ it often is found on Eastern icons (see illustration above), where it is used to identify Mary.
Within the Orthodox and Catholic tradition, Mother of God has not been understood, nor been intended to be understood, as referring to Mary as Mother of God from eternity — that is, as Mother of God the Father — but only with reference to the birth of Jesus, that is, the Incarnation. This limitation in the meaning of Mother of God must be understood by the person employing the term. To make it explicit, it is sometimes translated Mother of God Incarnate.[10]
However, those reading or hearing the English phrase Mother of God as a translation of a Greek text cannot — unless they know the Greek text in question, or obtain additional information — know whether the phrase is a literal translation of Μήτηρ Θεού or an imprecise rendering of Θεοτόκος or one its Latin equivalents or equivalents in other languages.