Kaia is a name with multiple roots: in Scandinavian languages it's a short form of Katarina ("pure"); in Hawaiian it means "the sea"; in Estonian and Finnish Kaia is also a feminine name. A top-500 US baby name since 2010. Kaia Joi — American competitive cheerleader. The name's modern surge through the 2010s is directly traceable to Kaia Gerber's IMG debut.
Kaia 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 Kaia reduce to 4, The Builder. This is a traditional interpretive system, not a factual claim about the name.