[n] a male with the same parents as someone else; "my brother still lives with our parents"
[n] (Roman Catholic) a title given to a monk and used as form of address; "a Benedictine Brother"
[n] a male person who is a fellow member (of a fraternity or religion of other group); "none of his brothers would betray him"
[n] used as a term of address for those male persons engaged in the same movement; "Greetings, comrade!"
[n] a close friend who accompanies his buddies in their activities