The term Indo-European refers to the hypothetical common ancestor of a large family of languages spoken across Europe and parts of Asia, including Sanskrit, Latin, Greek, Germanic languages, and many others.
Aryan was historically used but is now considered outdated and imprecise.
Indo-Germanic is an older term, mostly used in German scholarship, but less common today.
Primitive Germanic refers specifically to the early stage of the Germanic branch, not the parent language of all these families.
