Half-brother n. : A brother by one parent, but not by both.

Example:
What are the rights of a half brother trying to get guardianship of my son?

Taxonomy
siblings, birth order, Sibling rivalry, parents, Foster siblings, Brothers, Sister, family, Regressive behavior, sibling relationship, adoptive parents, Irish twins, brothers and sisters, free encyclopedia, relationship, competition, law, Godparent.

Defination from the web:
Half sibling. A half sibling (half brother or half sister) is a sibling with one shared biological or adoptive parent. ... Father-in-law · Mother-in-law · Son-in-law · Daughter-in-law · Brother-in-law · Sister-in-law. Kinship ...