1.
brothers-in-law; stepbrothers
Brothers related by marriage (a spouse's brother or a sibling's husband) or by a parent's remarriage, rather than by blood.
彼は私の義兄弟です。
He is my brother-in-law.
母の再婚で、義兄弟ができた。
I got a stepbrother through my mother's remarriage.
義兄弟とはいえ、実の兄弟のように仲が良い。
Even though they are stepbrothers, they get along as if they were real siblings.
2.
sworn brothers; blood brothers
Men who have formed a bond of brotherhood through an oath or ceremony, though not biologically related. A concept common in historical and fictional contexts.
二人は義兄弟の契りを結んだ。
The two swore an oath of brotherhood.
三国志では、劉備・関羽・張飛が義兄弟となった場面が有名だ。
In the Romance of the Three Kingdoms, the scene where Liu Bei, Guan Yu, and Zhang Fei became sworn brothers is famous.
彼らは義兄弟として生涯助け合うことを誓った。
They pledged as sworn brothers to help each other for life.
USAGE:
義兄弟 covers several types of non-blood brotherhood. In modern usage, it most commonly refers to brothers-in-law or stepbrothers. In historical and literary contexts, it refers to sworn brotherhood.
RELATED TERMS:
- 義兄 (brother-in-law, older)
- 義弟 (brother-in-law, younger)
- 義姉妹 (sisters-in-law / stepsisters)
- 兄弟 (siblings, biological brothers)
PREFIX 義:
The prefix 義 marks family relationships formed through marriage or legal arrangement rather than by blood: 義父 (father-in-law), 義母 (mother-in-law), 義理の息子 (son-in-law).