Thadius is a distinctive boys' name in United States, ranking #8243 in 2008 with 10 recorded births. This places Thadius in the bottom 44% of ranked US boys' names for the year. Its actual usage is classified as Rare. The name reached its all-time peak in 1998 with 14 births ranking #4847. In 2008, approximately 1 in every 203,995 boys born was named Thadius. RISING Recent data shows the name is currently rising.