mother of a holy person
General term for the mother of a saint or holy figure; not limited to Christianity.
She is like a holy mother—gentle and caring.
In Buddhism, Lady Maya, the mother of Shakyamuni, is sometimes regarded as a holy mother.
Holy Mother; Virgin Mary; Our Lady
Specifically refers to the Virgin Mary in Christian contexts.
聖母マリアはキリスト教で崇敬されている。
The Virgin Mary is venerated in Christianity.
聖母 is a formal title meaning 'Holy Mother' used almost exclusively for the Virgin Mary, while マリア is her proper name and can also refer to other women named Mary, such as Mary Magdalene.
From 聖 (holy) + 母 (mother). The term is used both generically and as a Christian title for Mary.