Sidni is a distinctive girls' name in United States, ranking #8420 in 2003 with 13 recorded births. The name reached its all-time peak in 1999 with 19 births ranking #5627. Since 1996, the popularity has increased by 85.7%. In 2003, approximately 1 in every 140,542 girls born was named Sidni. FALLING Recent data shows the name is currently falling.