Where does “kieby” come from?

kieby (Polish) comes from Polish -by, from Old Polish -by, from Old Polish by, from Proto-Slavic *by.

Ancestry of “kieby”, step by step

StepLanguageWordMeaning
1Polish-byconditional mood marker
2Old Polish-by[[conditional mood
3Old Polishbyintroduces a clause of aim; to, so that, in order to
4Proto-Slavic*by—
Every word from Proto-Slavic *by →Every word from Old Polish -by →Every word from Polish -by →