Where does “Frederiko” come from?

Frederiko (Esperanto) comes from Proto-Germanic Friþurīks, from Proto-Germanic rīks, from Proto-Celtic rīxs, from Proto-Indo-European h₃rḗǵs, from Proto-Indo-European h₃reǵ- — to straighten, to right oneself; right; just.

Ancestry of “Frederiko”, step by step

StepLanguageWordMeaning
1Proto-GermanicFriþurīkspeaceful ruler; peace king, peaceful ruler; prace...
2Proto-Germanicrīksking, ruler
3Proto-Celticrīxsking
4Proto-Indo-Europeanh₃rḗǵsking, ruler
5Proto-Indo-Europeanh₃reǵ-to straighten, to right oneself; right; just
Every word from Proto-Indo-European h₃reǵ- →Every word from Proto-Indo-European h₃rḗǵs →Every word from Proto-Celtic rīxs →