Where does “Iseult” come from?

Iseult (English) comes from Old High German īs, from Proto-West Germanic īs, from Proto-Germanic īsą, from Proto-Indo-European h₁eyH- — ice, frost.

Ancestry of “Iseult”, step by step

StepLanguageWordMeaning
1Old High Germanīsice
2Proto-West Germanicīsice
3Proto-Germanicīsąice
4Proto-Indo-Europeanh₁eyH-ice, frost
Every word from Proto-Indo-European h₁eyH- →Every word from Proto-Germanic īsą →Every word from Proto-West Germanic īs →