Zillah (צִלָּה) means "shadow" or "shade" in Hebrew. In Genesis 4:19, Zillah was the second wife of Lamech — mother of Tubal-Cain, the first metalworker, and of Naamah.
Featured in Mark Twain's Letters from the Earth.
Zillah 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 Zillah reduce to 5, The Seeker. This is a traditional interpretive system, not a factual claim about the name.