Where does “тридцатилетний” come from?

тридцатилетний (Russian) comes from Russian три́дцать, from Russian три, from Macedonian трие, from Proto-Slavic trьje, from Proto-Balto-Slavic tríjes, from Proto-Indo-European *tréyes.

тридцатилетний (Russian): thirty-year; thirty-year-old

Definitions

  1. thirty-year; thirty-year-old

Ancestry of “тридцатилетний”, step by step

тридцатилетний traces back through two separate lines of ancestry.

via Russian три́дцать

StepLanguageWordMeaning
1Russianтри́дцатьthirty (30)
2Russianтриthree; second-person singular imperative...
3Macedonianтриеto rub
4Proto-Slavictrьjethree
5Proto-Balto-Slavictríjesthree
6Proto-Indo-European*tréyes—

via Russian ле́то

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