Fionna is a distinctive girls' name in United States, ranking #6892 in 2008 with 19 recorded births. The name reached its all-time peak in 2012 with 41 births ranking #3804. Since 1996, the popularity has increased by 58.3%. In 2008, approximately 1 in every 99,511 girls born was named Fionna. FALLING Recent data shows the name is currently falling.