Fionna is a distinctive girls' name in United States, ranking #4737 in 2001 with 25 recorded births. The name reached its all-time peak in 2012 with 41 births ranking #3804. Since 1996, the popularity has increased by 108.3%. In 2001, approximately 1 in every 72,022 girls born was named Fionna. FALLING Recent data shows the name is currently falling.