Fionna is a distinctive girls' name in United States, ranking #4845 in 2000 with 24 recorded births. The name reached its all-time peak in 2012 with 41 births ranking #3804. Since 1996, the popularity has increased by 100.0%. In 2000, approximately 1 in every 75,666 girls born was named Fionna. FALLING Recent data shows the name is currently falling.