Yalda (یلدا) is the Persian name for the winter solstice — the longest night of the year, celebrated as a major Iranian festival (Shab-e Yalda). The word comes from the Syriac, meaning "birth."
Yalda is widely used in Iran for daughters born around the solstice.
Yalda 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 Yalda reduce to 7, The Seeker. This is a traditional interpretive system, not a factual claim about the name.