brother

a male offspring having both parents in common with another offspring; a male sibling.

Also called half brother.  a male offspring having only one parent in common with another offspring.

a stepbrother.

a male numbered among the same kinship group, nationality, ethnicity, profession, etc., as another; an associate; a fellow member, fellow countryman, fellow man, etc..

a fraternity brother.

Ecclesiastical.

1. (often initial capital letter) a male numbered among the lay members of a religious organization that has a priesthood.

2. a man who devotes himself to the duties of a religious order without taking holy orders, or while preparing for holy orders.

brothers, all members of a particular racial or ethnic group, or of the human race in general.

All men are brothers.

Slang. fellow; buddy.

Brother, can you spare a dime?

Informal. a term used to refer to or address a fellow Black man; soul brother.

a male person having the same parents as another person

short for half-brother stepbrother

1. a male person belonging to the same group, profession, nationality, trade union, etc, as another or others; fellow member

2. ( as modifier )

   brother workers

comrade; friend: used as a form of address

Christianity

1. a member of a male religious order who undertakes work for the order without actually being in holy orders

2. a lay member of a male religious order