A brother by blood: a brother-german or half-brother, as distinguished from step-brothers.
An unrelated male considered to share such a strong relationship generally.
An unrelated male considered to share a brother-like relationship established by a ceremonial sharing of blood in some cultures.
The stepdaughter of one's parent which is not one's half-sister.
The daughter of one's stepparent who is not the daughter of either of one's parents.