What is the meaning of Brother?

Son of the same parents as another person.

A male having at least one parent in common with another (see half-brother, stepbrother).

A male fellow member of a religious community, church, trades union etc.

A form of address to a man.

A fellow black man.

Somebody, usually male, connected by a common cause, situation, or affection.

Someone who is a peer, whether male or female.

Someone who is a kinsman or shares the same patriarch.

To treat as a brother.

Expressing exasperation.

A brother or brother-in-law; a male sibling.

A (Christian) man (i.e. as a "brother in life/brother in Christ").

A blood brother; one in a mutual pact of loyalty between two.

Another member of a religious community or order (when one is a member)

Another member of a guild or craft association (when one is a member)

A male individual who one has a close platonic relationship with.

One of one's peers as a ruler; (another) ruler.

A relative or family member who is a man.

Something similar to something else.

brother

bro (close friend)

Alternative form of brither

Source: wiktionary.org