- according to one theory, the language family comprising the Indo-European and Anatolian languages: most scholars now believe Anatolian to be a branch of Indo-European
- the hypothetical parent language from which the Indo-European and Anatolian languages descended
See Indo-Hittite in American Heritage Dictionary 4
- The Indo-European language family considered from the viewpoint that Proto-Indo-European as traditionally reconstructed is the sister and not the ancestor of Anatolian.
- The hypothetical parent language of Indo-European and Anatolian.