Where does “pełnoletnia” come from?

pełnoletnia (Polish) comes from Polish pełnoletni, from Polish letni, from Polish lato, from Proto-Slavic lěto, from Proto-Indo-European leh₁tóm.

Ancestry of “pełnoletnia”, step by step

StepLanguageWordMeaning
1Polishpełnoletnihaving legal age
2Polishletnisummer, summery, estival
3Polishlatosummer
4Proto-Slaviclětosummer; year
5Proto-Indo-Europeanleh₁tóm
Every word from Proto-Indo-European leh₁tómEvery word from Proto-Slavic lětoEvery word from Polish lato
pełnoletnia — Etymology, Origin & Word History | Etymology Explorer