Nana has parallel meanings. In Japanese (七), it means "seven" — the number of completeness. In Greek and many languages, Nana is the affectionate term for grandmother. In Akan, Nana is a royal title for both kings and queens.
Nana is the iconic dog-nanny in J.M. Barrie's Peter Pan; the manga and anime Nana by Ai Yazawa is a cultural phenomenon.
Nana 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 Nana reduce to 3, The Communicator. This is a traditional interpretive system, not a factual claim about the name.