1) a brother, whether born of the same two parents or only of the
    same father or mother
 2) having the same national ancestor, belonging to the same
    people, or countryman
 3) any fellow or man
 4) a fellow believer, united to another by the bond of affection
 5) an associate in employment or office
 6) brethren in Christ
    6a) his brothers by blood
    6b) all men
    6c) apostles
    6d) Christians, as those who are exalted to the same heavenly place