Fionna is a distinctive girls' name in United States, ranking #5970 in 1997 with 16 recorded births. The name reached its all-time peak in 2012 with 41 births ranking #3804. Since 1996, the popularity has increased by 33.3%. In 1997, approximately 1 in every 108,791 girls born was named Fionna. FALLING Recent data shows the name is currently falling.