The word brother refers to a male sibling. It is different from the word sister, which refers to a female sibling. In a family, a brother is a first-degree relative. The term brother is often used to describe a male sibling, but it can also apply to a female sibling.
A brother is often a male who shares common parents. It is also sometimes used for a male who is a member of a religious order. Other uses of the word brother include a male who is a peer of another person. A male can be a brother or a half brother. It’s also a word used to describe a person’s male peers, who are similar in appearance and physical features.
The word brother was first used in Middle English, and it comes from Old English brothor, which comes from Proto-Indo-European *bhreh2ter. The word brother has also been derived from Irish brathair, Latin frater, Ancient Greek phrater, and Persian brdr.