Fionna is a distinctive girls' name in United States, ranking #3804 in 2012 with 41 recorded births. This places Fionna in the top 19% of ranked US girls' names for the year. Its actual usage is classified as Rare. The name reached its all-time peak in 2012 with 41 births ranking #3804. Since 1996, the popularity has increased by 241.7%. In 2012, approximately 1 in every 42,945 girls born was named Fionna. FALLING Recent data shows the name is currently falling.