In Indo-European linguistics, the term Indo-Hittite (also Indo-Anatolian) refers to Edgar Howard Sturtevant's 1926 hypothesis that the Anatolian languages split off a Pre-Proto-Indo-European language considerably earlier than the separation of the remaining Indo-European languages. The prefix Indo- does not refer to the Indo-Aryan branch in particular, but stands for Indo-European, and the -Hittite part refers to the Anatolian language family as a whole.
Proponents of the Indo-Hittite hypothesis claim the separation preceded the spread of the remaining branches by several millennia, possibly as early as 7000 BC. In this context, the proto-language before the split of Anatolian would be called Proto-Indo-Hittite, and the proto-language of the remaining branches, before the next split, presumably of Tocharian, would be called Proto-Indo-European (PIE). This is a matter of terminology, though, as the hypothesis does not dispute the ultimate genetic relation of Anatolian with Indo-European; it just means to emphasize the assumed magnitude of temporal separation.