Esmeralda is the Spanish and Portuguese word for "emerald" — from the Greek smaragdos, the Greek-Roman word for the precious green gemstone.
Today Esmeralda sits in the U.S. top 400.
Esmeralda 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 Esmeralda reduce to 6, The Nurturer. This is a traditional interpretive system, not a factual claim about the name.