Sidnei is a distinctive girls' name in United States, ranking #16566 in 2012 with 6 recorded births. This places Sidnei in the bottom 15% of ranked US girls' names for the year. Its actual usage is classified as Rare. The name reached its all-time peak in 2006 with 7 births ranking #14927. In 2012, approximately 1 in every 293,457 girls born was named Sidnei. FALLING Recent data shows the name is currently falling.