Female names:
Odarka is the Ukrainian and Belarusian form of Darya, a feminine form of Darius. It ultimately derives from Persian name Dārayavahush (possessing goodness).
Oksana is the Ukrainian form of Xenia (hospitality). An alternative form is Oksaniya.
Oleksandra is the Ukrainian form of Alexandra (helper/defender of man). One of the nicknames is Olesya.
Olena is the Ukrainian form of Helen, which comes from Greek name Helene and probably means “torch” or “corposant.” Other sources believe it’s related to selene (moon).
Olha is the Ukrainian form of Olga, which derives from Old Norse name Helga (blessed, holy).
Oryna is an alternate form of Iryna, which comes from Greek name Eirene (peace). One of the nicknames is Orysya.
Male names:
Okhrim is a folk form of Ephraim, which comes from Hebrew name Efrayim (fruitful).
Olefir comes from Greek name Eleutherios (free).
Oleh is the Ukrainian form of the Russian name Oleg, which derives from Old Norse name Helgi (blessed, holy).
Oleksandr is the Ukrainian form of Alexander (helper/defender of man).
Oleksiy is the Ukrainian form of Alexis (defender/helper).
Olherd comes from Lithuanian name Algirdas, which possibly derives from Baltic roots al (each) and girdas (news, rumour).
Omelyan is the Ukrainian form of Emilian, which ultimately derives from Roman family name Aemilius (rival).
Ostap comes from Greek name Eustathius (well-built, stable).