Where does “tjugu” come from?

tjugu (Old Norse) comes from Old Norse tuttugu, from Proto-Germanic twai tigiwiz, from Proto-Germanic twai, from Proto-Indo-European dwóh₁ — two.

Ancestry of “tjugu”, step by step

StepLanguageWordMeaning
1Old Norsetuttugutwenty
2Proto-Germanictwai tigiwiztwenty
3Proto-Germanictwaitwo
4Proto-Indo-Europeandwóh₁two

Words derived from “tjugu”

Every word from Proto-Indo-European dwóh₁ →Every word from Proto-Germanic twai →Every word from Proto-Germanic twai tigiwiz →