Sidni is a distinctive girls' name in United States, ranking #6126 in 1997 with 16 recorded births. The name reached its all-time peak in 1999 with 19 births ranking #5627. Since 1996, the popularity has increased by 128.6%. In 1997, approximately 1 in every 108,791 girls born was named Sidni. FALLING Recent data shows the name is currently falling.