Fionna is a distinctive girls' name in United States, ranking #4918 in 1999 with 22 recorded births. The name reached its all-time peak in 2012 with 41 births ranking #3804. Since 1996, the popularity has increased by 83.3%. In 1999, approximately 1 in every 80,626 girls born was named Fionna. FALLING Recent data shows the name is currently falling.