Thaddius is a distinctive boys' name in United States, ranking #6474 in 1999 with 10 recorded births. The name reached its all-time peak in 2001 with 12 births ranking #5975. Since 1996, the popularity has increased by 66.7%. In 1999, approximately 1 in every 192,009 boys born was named Thaddius. FALLING Recent data shows the name is currently falling.