Real Dictionary

Indo-European in American English
designating or of a family of languages that includes most of those spoken in Europe and many of those spoken in southwestern Asia and India
the Indo-European family of languages: its principal branches are Albanian, Anatolian, Armenian, Baltic, Celtic, Germanic, Greek, Indic, Iranian (often grouped with Indic as the Indo-Iranian subfamily), Italic, Slavic, and Tocharian
adjective: of or belonging to Indo-European
noun: a large, widespread family of languages, the surviving branches of which include Italic, Slavic, Baltic, Hellenic, Celtic, Germanic, and Indo-Iranian, spoken by about half the world's population: English, Spanish, German, Latin, Greek, Russian, Albanian,

Indo-European in British English
adjective: denoting, belonging to, or relating to a family of languages that includes English and many other culturally and politically important languages of the world: a characteristic feature, esp of the older languages such as Latin, Greek, and Sanskrit, is infl
noun: the Indo-European family of languages