Oksana is the Ukrainian form of Xenia — from the Greek xenia, meaning "hospitality" or "stranger." Popularised by the heroine of Mykola Lysenko's opera Christmas Eve.
Oksana is widely used in Ukraine. Oksana Baiul (born 1977) is the Ukrainian Olympic figure-skating champion.
Oksana does not currently appear in the US Social Security Administration's top 1,000 girls' names, so we don't publish a US rank or birth count for it. That says nothing about the name's standing elsewhere in the world — only that it sits outside the ranked US data we rely on.
In Pythagorean numerology the letters of Oksana reduce to 7, The Seeker. This is a traditional interpretive system, not a factual claim about the name.