The fifth line of Aia María, Tolkien’s translation of the Ave Maria prayer. The first word airë “holy” is either an adjective or a form of address applied to the second word, María: the Quenyarized form of “Mary”. The third word Eruo “of God” is the genitive form of Eru “God”. The last word ontaril “mother” seems to be a feminine form of ᴹQ. ontaro “begetter, parent” (as suggested by the Wynne, Smith and Hostetter, VT43/32). If so, Eruo ontaril more literally means “✱genetrix (female begetter) of God”.
Decomposition: Broken into its constituent elements, this phrase would be:
> Airë María Eru-o ontaril = “✱holy Mary God-of genetrix”
Conceptual Development: In the second version of the prayer, Tolkien used {Aini >>} aina (II) for “holy” instead of aire (I, III-IV). In the first two versions of the prayer Tolkien used Eruamillë (I-II) for “Mother of God”, a compound of Eru “God” and amil(lë) “mother”.
|  I  | II |III|IV| |Aire|{Aini >>} Aina|Aire| |María| |Eruamille|Eruo| | |ontaril|
A title for Mary as the Mother of God in early drafts of Aia María, Tolkien’s translation of the Ave Maria prayer (VT43/26-7), and also as a rejected word in Ortírielyanna, Tolkien’s Quenya translation of the Sub Tuum Praesidium (VT44/5). It is a compound of Eru “God” and amil(lë) “mother”. In later drafts of Aia María, this name was replaced by the term Eruo ontaril (VT43/27-28), and in the translation of other prayers he used the name Eruontarië of similar meaning.