Etymology

From Proto-Germanic *rīkijaz, a derivative of *rīks ‎(“king, ruler”), itself a borrowing from Proto-Celtic *rīxs, from Proto-Indo-European *h₃rḗǵs. Compare Old English rīċe, Old Saxon rīki, Old High German rīhhi, Gothic 𐍂𐌴𐌹𐌺𐍃 ‎(reiks). See also the related term ríki.