Nyimas is from the Sundanese / Javanese Nyi Mas — Nyi (lady) + Mas (gold/noble) — Lady Gold, noble lady honorific. Nyimas is one of the Sundanese + Javanese feminine names — central to traditional Sundanese + Javanese royal-aristocratic naming heritage.
Nyimas 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 Nyimas reduce to 9, The Giver. This is a traditional interpretive system, not a factual claim about the name.