Where does “denko” come from?

denko (Polish) comes from Polish dno, from Proto-Slavic dъno, from Proto-Indo-European *dʰewb-.

Ancestry of “denko”, step by step

StepLanguageWordMeaning
1Polishdnobottom; vocative singular of dna
2Proto-Slavicdъnobottom
3Proto-Indo-European*dʰewb-—
Every word from Proto-Indo-European *dʰewb- →Every word from Proto-Slavic dъno →Every word from Polish dno →