Legal Definitions - brother-in-law

A brother-in-law is the brother of one's spouse or the husband of one's sister. The term can also refer to the husband of one's spouse's sister.

A brother-in-law refers to a male relative by marriage, typically in one of three ways:

• The brother of one's spouse.
• The husband of one's sister.
• Less commonly, the husband of one's spouse's sister.

Here are some examples illustrating the different ways someone can be a brother-in-law:

• Example 1: Brother of one's spouse

  When Emily married Thomas, she became part of his family. Thomas has a younger brother named Daniel. Daniel is Emily's brother-in-law because he is the brother of her husband.

• Example 2: Husband of one's sister

  Mark's sister, Sarah, recently got married to James. James is now Mark's brother-in-law because he is the husband of Mark's sister.

• Example 3: Husband of one's spouse's sister

  Jessica is married to Robert. Robert has a sister, Laura, who is married to Kevin. In this scenario, Kevin is often referred to as Jessica's brother-in-law because he is married to her husband's sister.