From Longman Dictionary of Contemporary Englishhalf-brotherˈhalf-ˌbrother ●●○ noun [countable] SSFa brother who is the son of only one of your parents → half-sister
Examples from the Corpus
half-brother• Other characters include his half brother, two male teachers and the male head teacher.• Sir Kenneth was the half brother of Osgood MacKenzie who created the famous gardens in Inverewe.• The president's half brother and one of his sons sued the government for trampling on their civil rights!