A male having the same parents as another or one parent in common with another.
One who shares a common ancestry, allegiance, character, or purpose with another or others, especially:
A kinsman.
A fellow man.
A fellow member, as of a fraternity, trade union, or panel of judges on a court.
A close male friend; a comrade.
A fellow African-American man or boy.
Something, such as a corporation or institution, that is regarded as a member of a class: "A station that ... relies on corporate contributions or advertising to survive runs the risk of becoming virtually indistinguishable from its commercial brethren” ( W. John Moore).
A member of a men's religious order who is not in holy orders but engages in the work of the order.