1a man or boy in relation to other sons and daughters of his parents:he recognized her from her strong resemblance to her brother
a male associate or fellow member of an organization:the time is coming, brothers, for us to act
(also brotha or brutha)North American informal a black man (often used as a term of address by other black people):there I was with one white boy and this other brother
a thing which resembles or is connected to another thing:the machine is almost identical to its larger brother
2 (plural also brethren /ˈbrɛðrɪn/) Christian Church a (male) fellow Christian.
a member of a religious order of men:a Benedictine brother
a member of a fundamentalist Protestant denomination:the Plymouth Brethren
be one's brother's keeper
be responsible for the behaviour of a relative, friend, or associate:we are, it seems, at last becoming a world in which each of us is our brother’s keeper
