Proto-Indo-European

Short definition from Wiktionary

Proper noun

1. 1
   The reconstructed ancestor language or protolanguage of the Indo-European family of languages, which includes most European, Iranian, and Indian languages.

Noun

1. 1
   A person who spoke the Proto-Indo-European language.

Adjective

1. 1
   Of or pertaining to the Proto-Indo-European language, or the people who spoke it.