Where does “дългъ” come from?

дългъ (Old East Slavic) comes from Proto-Slavic dь̀lgъ, from Proto-Balto-Slavic dílˀgas, from Proto-Indo-European dl̥h₁gʰós — long.

Ancestry of “дългъ”, step by step

StepLanguageWordMeaning
1Proto-Slavicdь̀lgъlong
2Proto-Balto-Slavicdílˀgaslong
3Proto-Indo-Europeandl̥h₁gʰóslong
Every word from Proto-Indo-European dl̥h₁gʰós →Every word from Proto-Balto-Slavic dílˀgas →Every word from Proto-Slavic dь̀lgъ →