Where does “samoděržaví” come from?

samoděržaví (Czech) comes from Russian самодержа́вие, from Russian само́-, from Russian сам, from Old East Slavic самъ, from Proto-Slavic samъ, from Proto-Balto-Slavic *sāmas, from Proto-Indo-European somHós, from Proto-Indo-European sem- — together, one.

samoděržaví (Czech): (tsarist) autocracy

Definitions

(tsarist) autocracy

Ancestry of “samoděržaví”, step by step

Step	Language	Word	Meaning
1	Russian	самодержа́вие	autocracy
2	Russian	само́-	self-
3	Russian	сам	self, -self
4	Old East Slavic	самъ	self, oneself, alone
5	Proto-Slavic	samъ	self, oneself
6	Proto-Balto-Slavic	*sāmas	—
7	Proto-Indo-European	somHós	same, alike
8	Proto-Indo-European	sem-	together, one

Every word from Proto-Indo-European sem- →Every word from Proto-Indo-European somHós →Every word from Proto-Balto-Slavic *sāmas →