What is the meaning of Brother-in-law?

A male relative of one's generation, separated by one degree of marriage:

  1. The brother of one's spouse.
  2. The husband of one's sibling.

The brother of one's spouse.

The husband of one's sibling.

Co-brother-in-law: A male relative of one's generation, separated by two degrees of marriage:

  1. The husband of the sibling of one's spouse.
  2. The brother of the spouse of one's sibling.

The husband of the sibling of one's spouse.

The brother of the spouse of one's sibling.

Source: wiktionary.org