Collins Russian Dictionary 2nd Edition © HarperCollins Publishers 2000, 1997:
half-brother [ˈhɑːfbrʌðər] n (with same mother) единоутро́бный брат#; (with same father) единокро́вный брат#
* is used to mark translations which have irregular inflections. The Russian-English side of the dictionary gives inflectional information.
Русский: