Brother-in-law (noun)

1. The brother of one's spouse.
2. A man who is the brother of one's spouse.

Origin:

Brother + -in-law, first recorded in the 14th century.

Examples:

1. He is my brother-in-law.
2. My brother-in-law is a lawyer.
3. He and my brother-in-law play golf together.
4. I went to my brother-in-law's wedding.
5. He is the brother-in-law of the groom.