a son of the same parents as another person
male sibling
Cases of word usage
1) an act of sexual intercourse between close relations, e.g. a brother and sister (incest)
2) a son of one's brother or sister (nephew)
3) a daughter of one's brother or sister (niece)
4) a brother or sister (the usual word) (sibling)
5) the brother of one's father or mother; the husband of one's aunt (uncle)