Fionna is a distinctive girls' name in United States, ranking #7378 in 2021 with 15 recorded births. The name reached its all-time peak in 2012 with 41 births ranking #3804. Since 1996, the popularity has increased by 25.0%. In 2021, approximately 1 in every 109,314 girls born was named Fionna. FALLING Recent data shows the name is currently falling.