Where does “двадцатилетний” come from?

двадцатилетний (Russian) comes from Russian двадца́ть, from Russian два, from Old East Slavic дъва, from Proto-Slavic dъva, from Proto-Balto-Slavic duwō, from Proto-Indo-European dwóh₁ — two.

двадцатилетний (Russian): twenty-year; twenty-year-old

Definitions

  1. twenty-year; twenty-year-old

Ancestry of “двадцатилетний”, step by step

двадцатилетний traces back through two separate lines of ancestry.

via Russian двадца́ть

StepLanguageWordMeaning
1Russianдвадца́тьtwenty (20)
2Russianдваtwo
3Old East Slavicдъваtwo
4Proto-Slavicdъvatwo
5Proto-Balto-Slavicduwōtwo
6Proto-Indo-Europeandwóh₁two

via Russian ле́то

StepLanguageWordMeaning
1Russianле́тоyear; summer, year
2Old East Slavicлѣтоtime
3Proto-Slaviclětosummer; year
4Proto-Indo-Europeanleh₁tóm—
Every word from Proto-Indo-European dwóh₁ →Every word from Proto-Balto-Slavic duwō →Every word from Proto-Slavic dъva →