The two Chinese characters in the word Mizu-ko are literally translated "water" and "baby". It is the term used in Japan to describe the spirit of a child that has died inutero through miscarriage, stillbirth or abortion. There is no equivalent English word for an unborn foetus.
I found it comforting to be able to put such a beautiful word to my lost one.
The two Chinese characters in the word Ku-yo are literally translated as "to offer" and "to nourish". In Japan, the word Kuyo refers to a ritual or ceremony. Therefore the expression Mizuko Kuyo refers to a ceremony that acknowledges the loss of infants that have died inutero through miscarriage, stillbirth or abortion. Buddhist monks conduct Mizuko Kuyo ceremonies in Zen Buddhist temples. The central element to the Mizuko Kuyo ceremony is a figure of Mizuko Jizo (see below).
When I visited Japan, I met a monk who was pleased to know that I was inspired by their tradition. He said the only requirement for the Mizuko Kuyo ceremony is that the mother says a prayer for the Mizuko. As a non-Buddhist I chose to conduct my own Kuyo ceremony with my family in our garden.
To the Japanese, Jizo is a much-loved Bodhisattva (or saint) in Zen Buddhism. Jizo by itself is the protector of children and travelers. However the Mizuko Jizo specifically protects the spirit of a child that has died inutero through miscarriage, stillbirth or abortion.