Where does “pääsiäislauantai” come from?

pääsiäislauantai (Finnish) comes from Finnish lauantai, from Old Norse laugardagr, from Old Norse laug, from Proto-Germanic laugō, from Proto-Indo-European lewh₃- — to wash.

Ancestry of “pääsiäislauantai”, step by step

pääsiäislauantai traces back through two separate lines of ancestry.

via Finnish lauantai

StepLanguageWordMeaning
1FinnishlauantaiSaturday
2Old NorselaugardagrSaturday
3Old Norselaugbath; hot spring; first-person singular past...
4Proto-Germaniclaugōbath, wash; soap, lye
5Proto-Indo-Europeanlewh₃-to wash

via Finnish pääsiäinen

StepLanguageWordMeaning
1FinnishpääsiäinenEaster
2Finnishpäästäto get to, reach, arrive at/in; to get to go, be...
3Finnishpäähead; end, tip
4Proto-Finnicpäähead
5Proto-Uralicpäŋehead
Every word from Proto-Indo-European lewh₃-Every word from Proto-Germanic laugōEvery word from Old Norse laug