proethnic UK /pɹəʊˈɛθ.nɪk/US /pɹoʊˈɛθ.nɪk/ adjective1 •of or pertaining to the period prior to the split of the Proto-Indo-European language into the Indo-European language familyThe original meaning of the root is 'put'; but, from the proethnic period, a secondary development in the line ('set,' 'establish,' and so) 'make,' 'do,' is clear. — 1888