Vasiliki is from the Greek Βασιλική (Vasilikí — queenly, royal) — feminine of Vasilios (king). Vasiliki is one of the Greek feminine names — central to traditional Greek Orthodox heritage. The -iki feminine suffix is one of the Greek feminine-naming patterns.
Vasiliki 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 Vasiliki reduce to 2, The Peacemaker. This is a traditional interpretive system, not a factual claim about the name.