The traditional etymology is from the name the a legendary founder кии (kii, in Old Church Slavonic), mentioned in the Hypatian Codex (see Kyi, Shchek and Khoryv on Wikipedia). Compare Ukrainian Кий (Kyj), Russian Ки́ев (Kíjev) and Кий (Kij). However, historian Michael Hrushevsky warned that this was an “etymological myth”.
A proposal by linguist Jaroslav Rudnyckyj, accepted by several émigré linguists and supported by multiple lines of evidence, holds that Київ comes rather from кий (kyj, “stick, pole”), meaning a settlement palisaded ки́ями (kýjamy, “by poles”). The word comes from Proto-Slavic *kyjь (“pole, hammer”), from Proto-Indo-European *kū-i̯os (“pole, hammer”), *kāu̯-, *kəu̯-, related to *kūti (“to hit”), from *koutei.
- Kiev (the capital of Ukraine)
- Melʹnyčuk O. S., editor (1982–2012), “кий”, in Etymolohičnyj slovnyk ukrajinsʹkoji movy [Etymological Dictionary of the Ukrainian Language] (in Ukrainian), Kiev: Naukova Dumka
- Rudnycʼkyj, Jaroslav B. (1982), “Київ”, in An Etymological Dictionary of the Ukrainian Language (in Ukrainian), volume II, Ottawa: Ukrainian Mohylo-Mazepian Academy of Sciences, Ukrainian Language Association, pages 660–667