Proto-Germanic

[proh-toh-jer-man-ik] /ˌproʊ toʊ dʒərˈmæn ɪk/
noun
1.
the unattested prehistoric parent language of the Germanic languages; Germanic.
adjective
2.
of or pertaining to Proto-Germanic.
British Dictionary definitions for Proto-Germanic

Proto-Germanic

noun
1.
the prehistoric unrecorded language that was the ancestor of all Germanic languages