Fæderen-bróðor

According to the Old English Dictionary:

es;

fæderen-bróðor

m. A brother from the same father; frāter ex eōdem patre ŏriundus :-- Ic fram ðé wearþ fæderenbróðrum exter factus sum fratribus meis, Ps. Th. 68, 8. fæderen-broðor