Erna is from the Old Norse Erna — feminine of Erni, meaning "vigorous, brisk" — also linked to the Germanic ern (eagle). Leader of the Conservative Party (Høyre) since 2004. Has been open about her dyslexia diagnosis from childhood — credited with making her a global advocate for learning-disability accommodations.
Erna 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 Erna reduce to 2, The Peacemaker. This is a traditional interpretive system, not a factual claim about the name.