Sidni is a distinctive girls' name in United States, ranking #16995 in 2009 with 6 recorded births. The name reached its all-time peak in 1999 with 19 births ranking #5627. Since 1996, the popularity has decreased by 14.3%. In 2009, approximately 1 in every 306,145 girls born was named Sidni. FALLING Recent data shows the name is currently falling.