adj. & n.
adj. 1 of or relating to the family of languages spoken over the greater part of Europe and Asia as far as n. India. 2 of or relating to the hypothetical parent language of this family.
n. 1 the Indo-European family of languages. 2 the hypothetical parent language of all languages belonging to this family. 3 (usu. in pl.) a speaker of an Indo-European language.