1
- of or relating to the family of languages spoken over the greater part of Europe and Asia as far as northern India（与）印欧语系（有关）的。
The Indo-European languages have a history of over 3,000 years. Their unattested, reconstructed ancestor, Proto-Indo-European, is believed to have been spoken well before 4,000 BC in a region somewhere to the north or south of the Black Sea. The family comprises twelve branches: Indic (including Sanskrit and its descendants), Iranian, Anatolian (including Hittite and other extinct languages), Armenian, Hellenic (Greek), Albanian (or Illyrian), Italic (including Latin and the Romance languages), Celtic, Tocharian (an extinct group from central Asia), Germanic （including English, German, Dutch, and the Scandinavian languages）, Baltic, and Slavic （including Russian, Czech, Bulgarian, and Serbo-Croat）.
1
- mass noun the ancestral Proto-Indo-European language原始印欧语。
1.1
- the Indo-European family of languages印欧语系。
2
- a speaker of an Indo-European language, especially Proto-Indo-European操印欧语系语言（尤指原始印欧语）的人。