Fiona is a Scottish name from the Gaelic fionn, meaning "fair" or "white" — the same root that gives the masculine Finn and the Irish Fionnuala. The name was popularised by the 19th-century Scottish poet William Sharp, who wrote under the pseudonym "Fiona Macleod."
Fiona entered the U.S. top 1000 in 1990 and has been climbing. Today it sits in the U.S. top 250.
Fiona 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 Fiona reduce to 9, The Giver. This is a traditional interpretive system, not a factual claim about the name.