Xanthi is from the Greek Ξανθή (Xanthí — blonde, golden, fair-haired). Xanthi is one of the Greek feminine names — central to traditional Greek Orthodox heritage. Greek feminine name reflecting Greek heritage.
Xanthi 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.
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In Pythagorean numerology the letters of Xanthi reduce to 4, The Builder. This is a traditional interpretive system, not a factual claim about the name.