Seith is a distinctive boys' name in United States, ranking #13027 in 2005 with 5 recorded births. This places Seith in the bottom 3% of ranked US boys' names for the year. Its actual usage is classified as Rare. The name reached its all-time peak in 1999 with 12 births ranking #5595. Since 1996, the popularity has decreased by 16.7%. In 2005, approximately 1 in every 399,429 boys born was named Seith. FALLING Recent data shows the name is currently falling.