外がい孫そん

noun

grandchild from a daughter married into another family

Refers specifically to the child of one's daughter who has married out of the family, as opposed to 内孫 (uchi-mago), the child of a son who remains in the family. This distinction is traditional and may not be observed in all modern families.

• 娘むすめが嫁とついだ先さきで生うまれた子こは外そと孫まごと呼よばれる。

  A child born to a daughter who has married into another family is called a sotomago.

• 外そと孫まごは姓せいが違ちがうので、家いえの跡あと継つぎにはならない。

  Since a sotomago has a different family name, they do not become the heir of the household.