Artemisia is from the Greek goddess Artemis. Artemisia Gentileschi (1593-c. 1656) was the most important female Baroque painter — best known for her dramatic Judith Slaying Holofernes (c.
Subject of Mary Garrard's Artemisia Gentileschi (1989).
Artemisia 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 Artemisia reduce to 5, The Seeker. This is a traditional interpretive system, not a factual claim about the name.