Where does “義兄弟” come from?

義兄弟 (Japanese) comes from Japanese 兄弟, from Japanese 兄, from Old Japanese あに, from Japanese の, from Old Japanese の, from Middle Chinese 能 — talent, ability.

義兄弟 (Japanese): sworn brothers

Definitions

  1. sworn brothers

Ancestry of “義兄弟”, step by step

義兄弟 traces back through two separate lines of ancestry.

via Japanese 兄弟

StepLanguageWordMeaning
1Japanese兄弟brothers; siblings; brothers and sisters;...
2Japanese兄elder brother; elder brother-in-law; Short for...
3Old Japaneseあに—
4Japaneseのgenitive case marker; nominative case marker in a...
5Old Japaneseのplain, field
6Middle Chinese能talent, ability

via Japanese 義

StepLanguageWordMeaning
1Japanese義justice; a situation which has a right and proper...
Every word from Middle Chinese 能 →Every word from Old Japanese の →Every word from Japanese の →