Mother-in-law - Kabo

...A clan has a system of order, and people occupy a certain position within it, which regulates their status and their relationship with the law of the state, and each person must have a code of conduct according to their kinship name, that is, their name. For example, in the case of a mother, the biological mother is called the parent, the child of a concubine is called the father's legal wife, the child of a former wife is called the second wife, the child of a concubine is called the stepmother, when a child of a concubine loses his biological mother and is brought up by another concubine, the concubine is called the loving mother, an adopted child's foster parent's wife is called the adoptive mother, a divorced parent is called the stepmother, a widowed parent who marries someone else is called the bride's mother, a father's concubine with children is called the other child's stepmother, and a father's concubine who breastfed the child is called the wet nurse. Excluding parents, these are called the "eight mothers," and not only are there detailed gradual mourning periods for each of them under the ceremonial system, but they also have a certain treatment under the Ritsuryo system.

*Some of the terminology that refers to "mother-in-law" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…宗族は秩序の体系を持っており，人々はその中で一定の地位を占め，そのことから身分関係や国家の法との関係を規制され，各人は親族名称，すなわち〈名〉に応じた行動規準を持たねばならない。全体は図4を参考に供するとして，たとえば〈はは〉についてみると，生みの母を〈親母〉，めかけの子は父の正妻を呼んで〈嫡母〉，前妻の子は後妻を呼んで〈継母〉，めかけの子がその生みの母を失い，他のめかけが養育するとそのめかけを〈慈母〉，養子は養い親の妻を〈養母〉，離婚された親母を〈出母〉，寡婦たる親母で他人に嫁いだものを〈嫁母〉，父のめかけで子あるものを他の子は〈庶母〉，父のめかけで己に乳を与えたものを〈乳母〉という。親母を除いてこれらを〈八母〉というが，それぞれに礼制上，服喪の期間などが細かく段階的に定められていることはもちろん，律の上でも一定の扱いがある。…

※「嫁母」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報