adoptive sibling

Noun

A person who is not one's biological sibling, but was legally and socially raised as if they were.

Japanese Meaning

養子縁組によって実の兄弟姉妹ではなくても、法律的・社会的に兄弟姉妹として扱われる人

My adoptive sibling and I celebrate our birthdays together every year.

私の養子の兄弟と私は毎年一緒に誕生日を祝います。

Sense（1）

A person who is not one's biological sibling, but was legally and socially raised as if they were.

adoptive siblings

（ plural ）