Reign is from the Latin regnum (kingdom, rule) — a modern American word-name in the broader 2010s aesthetic of royal/identity-affirming choices. A top-1000 US baby name since 2019.
Reign 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 Reign reduce to 8, The Visionary. This is a traditional interpretive system, not a factual claim about the name.