Translation guide
In Japanese, the term for brother-in-law depends on whether he is your spouse's brother or your sibling's husband, and on relative age in some cases. Politeness and family context also affect word choice.
Referring to the brother of your husband or wife.
Used when your spouse's brother is older than your spouse. Literally 'older brother by marriage'.
My brother-in-law (husband's older brother) lives in Tokyo.
Used when your spouse's brother is younger than your spouse. Literally 'younger brother by marriage'.
My brother-in-law (wife's younger brother) is a college student.
A more formal or written term for an older brother-in-law (spouse's older brother).
My brother-in-law (spouse's older brother) is a doctor.
A more formal or written term for a younger brother-in-law (spouse's younger brother).
My brother-in-law (spouse's younger brother) is still single.
Referring to the husband of your own brother or sister.
Used when your sister's husband is older than you, or when referring to your older sister's husband. Can also be used for your brother's husband if he is older than you.
My sister's husband, my brother-in-law, is good at cooking.
Used when your sister's husband is younger than you, or when referring to your younger sister's husband. Can also be used for your brother's husband if he is younger than you.
Formal term for an older brother-in-law (sibling's husband older than you).
Formal term for a younger brother-in-law (sibling's husband younger than you).
When the exact relationship or age difference is unknown or irrelevant, or when speaking generally.
English uses one term for multiple relationships, but Japanese requires specifying whether the person is a spouse's brother or a sibling's husband, and often their age relative to the speaker or spouse. Using a vague term like 義理の兄弟 is acceptable but less common in specific contexts.
In casual conversation, Japanese speakers often refer to a brother-in-law by name with an appropriate honorific (e.g., お兄さん for an older brother-in-law) rather than using a kinship term. This is especially common when addressing them directly.
My younger sister's husband, my brother-in-law, works at an IT company.
義兄は弁護士です。
My brother-in-law (older sister's husband) is a lawyer.
義弟は教師です。
My brother-in-law (younger sister's husband) is a teacher.
He is my brother-in-law (I'm not sure if he's older or younger).