Sidni is a distinctive girls' name in United States, ranking #6177 in 2000 with 18 recorded births. The name reached its all-time peak in 1999 with 19 births ranking #5627. Since 1996, the popularity has increased by 157.1%. In 2000, approximately 1 in every 100,887 girls born was named Sidni. FALLING Recent data shows the name is currently falling.