The Cozy Conundrum Of In-Law Nomenclature: Brother-In-Law's Sister

The term for a person's brother-in-law's sister or sister-in-law's brother varies depending on the context and the language used. In English, there is no widely recognised single-word term for this relationship. Commonly, individuals in this situation are referred to as brother-in-law's sister or sister-in-law's brother. However, in Spanish, the term concuñado/a is used to describe this relationship. In Indian English, the terms co-sister and co-brother are sometimes used to refer to the spouse of one's sibling-in-law.

Co-sister-in-law

The term "co-sister-in-law" is used to refer to the wife of one's sibling-in-law. In other words, it describes the relationship between two people who are each married to siblings. For example, if two pairs of siblings marry each other, the sisters in each couple would be co-sisters-in-law to each other. This term is not commonly used in everyday English conversation, and there is no single-word term for this relationship in the English language.

In Indian English, the term "co-sibling" is used, with "co-sister" referring specifically to the wife of one's sibling-in-law, and "co-brother" referring to the husband of one's sibling-in-law. In Spanish, the term "concuñado/a" is used for this relationship.

In general, English has relatively few kinship terms compared to many other languages. When referring to the wife of one's brother-in-law or sister-in-law, one might simply say "sister-in-law" or use a phrase like "my brother-in-law's sister."

Co-brother-in-law

The term "co-brother-in-law" is sometimes used to refer to the brother of one's brother-in-law or the brother of one's sister-in-law. This term is often used when translating from a language that has a specific word for this relationship into English, which does not have a commonly used word for this type of kinship. In Indian English, the term "co-sibling" is used, with "co-sister" referring to the wife of one's sibling-in-law and "co-brother" referring to the husband of one's sibling-in-law.

In general, English has relatively few kinship terms compared to many other languages. When referring to the brother of one's brother-in-law or sister-in-law, one might simply say "my brother-in-law's brother" or "my sister-in-law's brother." Alternatively, one could refer to the individual as "a friend" or "a brother-in-law" if a more precise relationship term is not needed.

In Spanish, the term "concuñado/a" is used to refer to the brother or sister of one's brother-in-law or sister-in-law. This term is commonly used in families with Spanish-speaking members.

Sister-in-law

A sister-in-law is the sister of your spouse. The term can also refer to the female spouse of your sibling. In Indian English, the wife of your sibling's spouse is known as a co-sister.

In some languages, there are specific terms for the relationship between the siblings of your siblings-in-law and yourself. For example, in Spanish, the term concuñado/a is used for the brother or sister of your brother or sister-in-law. In English, there is no commonly used single-word term for this relationship. Instead, you would refer to the person as the brother or sister of your brother or sister-in-law, or simply as a friend.

The children of your siblings-in-law are known as your cousins or distant cousins.

Brother-in-law's brother

The brother of your brother-in-law is not a standard named relation. However, the brother of your brother-in-law could be considered your brother-in-law, although this usage is uncommon.

To explain this in more detail, let's consider an example. Suppose your name is Alice, and you have a sister called Charlotte. Charlotte is married to Martin, and Martin has a brother called William. In this case, Martin is your brother-in-law. However, William is not your brother-in-law, although you could refer to him as such in casual conversation. This is because William is your sister's husband's brother, or your sister-in-law's brother.

Another way to understand this is by considering the opposite scenario. From William's perspective, Charlotte is his brother's wife, so she is William's sister-in-law. You, Alice, are Charlotte's sister, so you are William's sister-in-law's sister. This means that William and you are not related by marriage, although you could choose to refer to each other as brother- and sister-in-law if you wanted to.

In summary, while there is no widely accepted term for the brother of your brother-in-law, you could consider him to be your brother-in-law as well, especially if you have a close relationship.

No specific term

There is no specific term for a brother-in-law's sister. While the term sibling-in-law exists, it typically refers to the spouse of one's sibling or the sibling of one's spouse. In this context, it would refer to your brother-in-law's spouse, i.e., your spouse's sister.

Some cultures and languages do have specific terms for this relationship. For example, in Indian English, the terms "co-sister" and "co-brother" are used for the wife and husband of one's sibling-in-law, respectively. Similarly, in Spanish, the term "concuñado/a" is used for the sibling of one's sibling-in-law.

However, in English, there is no widely recognised single-word term for this relationship. The closest way to describe the relationship would be to say "my brother-in-law's sister" or "my sister's brother-in-law's sister". Alternatively, if you are close, you could simply refer to them as a friend or sister.

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