Where does “семидесятилетие” come from?

семидесятилетие (Russian) comes from Russian семьдесят, from Russian де́сять, from Old Church Slavonic десѧть, from Proto-Slavic desętь, from Proto-Balto-Slavic *déśimt, from Proto-Indo-European déḱm̥t — ten.

семидесятилетие (Russian): seventy-year period

Definitions

  1. seventy-year period

Ancestry of “семидесятилетие”, step by step

семидесятилетие traces back through two separate lines of ancestry.

via Russian семьдесят

StepLanguageWordMeaning
1Russianсемьдесятseventy
2Russianде́сятьten
3Old Church Slavonicдесѧтьten
4Proto-Slavicdesętьten
5Proto-Balto-Slavic*déśimtten
6Proto-Indo-Europeandéḱm̥tten

via Russian ле́то

StepLanguageWordMeaning
1Russianле́тоyear; summer, year
2Old East Slavicлѣтоtime
3Proto-Slaviclětosummer; year
4Proto-Indo-Europeanleh₁tóm—
Every word from Proto-Indo-European déḱm̥t →Every word from Proto-Balto-Slavic *déśimt →Every word from Proto-Slavic desętь →