Fionna is a distinctive girls' name in United States, ranking #4424 in 2004 with 31 recorded births. The name reached its all-time peak in 2012 with 41 births ranking #3804. Since 1996, the popularity has increased by 158.3%. In 2004, approximately 1 in every 59,230 girls born was named Fionna. FALLING Recent data shows the name is currently falling.