Where does “полусон” come from?

полусон (Russian) comes from Russian сон, from Proto-Slavic sъ̀nъ, from Proto-Balto-Slavic supnas, from Proto-Indo-European supnós, from Proto-Indo-European swóp-r̥ ~ swép-n̥s, from Proto-Indo-European swep- — to sleep.

полусон (Russian): half-sleep, twilight sleep

Definitions

  1. half-sleep, twilight sleep

Ancestry of “полусон”, step by step

StepLanguageWordMeaning
1Russianсонsleep; dream
2Proto-Slavicsъ̀nъsleep, dream
3Proto-Balto-Slavicsupnassleep, dream
4Proto-Indo-Europeansupnóssleep; death
5Proto-Indo-Europeanswóp-r̥ ~ swép-n̥s—
6Proto-Indo-Europeanswep-to sleep
Every word from Proto-Indo-European swep- →Every word from Proto-Indo-European swóp-r̥ ~ swép-n̥s →Every word from Proto-Indo-European supnós →