The Collaborative International Dictionary
Brother german
German \Ger"man\, a. [OE. german, germain, F. germain, fr. L. germanus full, own (said of brothers and sisters who have the same parents); akin to germen germ. Cf. Germ, Germane.] Nearly related; closely akin.
Wert thou a leopard, thou wert german to the lion.
--Shak.
Brother german. See Brother german.
Cousins german. See the Note under Cousin.
Brother german
Brother german \Broth"er ger"man\ (Law)
A brother by both the father's and mother's side, in
contradistinction to a uterine brother, one by the mother
only.
--Bouvier.
Wiktionary
brother german
n. a sibling that has two common parents, can also be used for sisters.