Киевъ

• Кꙑевъ (Kyevŭ)

Uncertain:

• Traditionally concidered to be derived from the city's founder Кии (Kii), meaning "Kii's [city]". This has been dismissed by Michael Hrushevsky as folk etymology.
• According to Jaroslav Rudnyckyj, the name derives from кии (kii, “pole”), referring to the fact the city was palisaded by poles.
• Alternatively, related to the modern Ukrainian куява (kujava, “steep hill”) and Ukrainian куеви (kuevy, “mountain top”).

Киевъ (Kievŭ) m

1. Kiev (a city in Kievan Rus)
   • 1377, Dmitry of Suzdal, Laurentian Codex‎, page 1:

     кто въ києвѣ нача первѣє кнѧжи^т и ѿкуду рускаꙗ ꙁемлѧ стала єсть⁘

     kto vŭ kievě nača pervěe knęži^t i otŭkudu ruskaja zemlę stala estĭ⁘

     Who in Kiev first started to reign and whence the Russian land has started to be.

• Middle Russian: Киевъ (Kijev), Киев (Kijev)
  • Russian: Ки́ев (Kíjev) (see there for further descendants)
• Old Ruthenian: Ки́євъ, Кї́євъ, Ки́ѣвъ
  • Belarusian: Кі́еў (Kíjeŭ)
  • Rusyn: Ки́їв (Kýjiv)
  • Ukrainian: Ки́їв (Kýjiv) (see there for further descendants)

• Trubachyov, Oleg, editor (1987), “*Kyjevъ”, in Этимологический словарь славянских языков [Etymological Dictionary of Slavic Languages] (in Russian), issue 13 (*kroměžirъ – *kyžiti), Moscow: Nauka, page 256
• Rudnyc'kyj, Ja. (1972–1982), “Ки́їв”, in An Etymological Dictionary of the Ukrainian Language, volume 2 (Д – Ь), issue 12–22, Ottawa: Ukr. Mohylo-Mazepian Acad. of Sci. & Ukr. Lang. Assoc., →LCCN, page 660
• Stryzhak, O. S., editor (1985), “Кыєвъ”, in Етимологічний словник літописних географічних назв Південної Русі [Etymological Dictionary of Chronicle Geographical Names of Southern Rus'] (in Ukrainian), Kyiv: Naukova Dumka, page 77
• Luchyk, V. V. (2014), “Київ”, in Етимологічний словник топонімів України [Etymological Dictionary of Toponyms of Ukraine] (in Ukrainian), Kyiv: Academy, →ISBN, page 259