Thaddius is a distinctive boys' name in United States, ranking #6564 in 1997 with 9 recorded births. The name reached its all-time peak in 2001 with 12 births ranking #5975. Since 1996, the popularity has increased by 50.0%. In 1997, approximately 1 in every 209,454 boys born was named Thaddius. FALLING Recent data shows the name is currently falling.