Thadius is a distinctive boys' name in United States, ranking #9007 in 2005 with 8 recorded births. The name reached its all-time peak in 1998 with 14 births ranking #4847. Since 1996, the popularity has decreased by 20.0%. In 2005, approximately 1 in every 249,643 boys born was named Thadius. RISING Recent data shows the name is currently rising.