Proto-IE: *reg'- (*rēg'-s)
Meaning: chief, king
Old Indian: rāj- m. `king', rā́jan- m. id., rā́jñī f. `queen', rā́jati, rā́ṣṭi `to reign, be king, rule over'; rā́jya-, rājyá-, rājyà- n. `royalty, kingship', rāṣṭrá- m. n. `kingdom, realm'
Avestan: rāstar- 'Lenker, Leiter'
Latin: rēx, gen. rēgis m. `Leiter, König, Fürst, Prinz; Despot, Oberhaupt; Patron; Erzieher'
Celtic: Gaul Catu-rīx, pl. -rīges, etc. `Kampfkönig(e)'; Rīgo-magus eig. `Königsfeld'; OIr rī, gen. rīg `König', rīgain `Königin', MIr rīge `Königreich'; Cymr rhi `Fürst', rhiain `Dame'; [ OCorn ruy, MBret roe, NBret roue ]
Russ. meaning: вождь, царь
