From Proto-Finnic *ku (from Proto-Uralic *ku- ~ *ko-) + -ka.
- Cognates with Estonian kumb (“which”), Hungarian hol (“where”), Forest Enets hōke (“which one”), Nganasan kuninu (“where”), and Kamassian kāmǝ̑n (“if”).
- Compare Proto-Indo-European *kʷi- ~ *kʷe- ~ *kʷo-, whence the English interrogatives English what, where, who, how derive.
Origin uncertain; perhaps an Italian loan word, compare Northern Italian cuco (“goofy”).
From Proto-Slavic *kuka (“hook, hook-shaped”). Akin to kȕk.