Catriona is the Scottish Gaelic form of Catherine — from the Greek katharos, "pure." Robert Louis Stevenson's novel Catriona (1893) is the sequel to Kidnapped.
Catriona is widely used in Scotland and the Scottish diaspora.
Catriona 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 Catriona reduce to 9, The Giver. This is a traditional interpretive system, not a factual claim about the name.