Where does “i dag” come from?

i dag (Swedish) comes from Old Swedish ī dagh, from Old Swedish dagher, from Old Norse dagr, from Proto-Germanic dagaz, from Proto-Indo-European dʰegʷʰ- — to burn; warm, hot.

Ancestry of “i dag”, step by step

StepLanguageWordMeaning
1Old Swedishī daghtoday
2Old Swedishdagherday
3Old Norsedagra day; days, times
4Proto-Germanicdagazday; name of the D-rune
5Proto-Indo-Europeandʰegʷʰ-to burn; warm, hot
Every word from Proto-Indo-European dʰegʷʰ- →Every word from Proto-Germanic dagaz →Every word from Old Norse dagr →