Kayin is a distinctive boys' name in United States, ranking #3945 in 2006 with 25 recorded births. This places Kayin in the top 28% of ranked US boys' names for the year. Its actual usage is classified as Rare. The name reached its all-time peak in 2001 with 31 births ranking #2964. Since 1996, the popularity has increased by 78.6%. In 2006, approximately 1 in every 82,205 boys born was named Kayin. FALLING Recent data shows the name is currently falling.