Thaddius is a distinctive boys' name in United States, ranking #13983 in 2016 with 5 recorded births. The name reached its all-time peak in 2001 with 12 births ranking #5975. Since 1996, the popularity has decreased by 16.7%. In 2016, approximately 1 in every 379,442 boys born was named Thaddius. FALLING Recent data shows the name is currently falling.