Thaddaeus is a distinctive boys' name in United States, ranking #3587 in 1998 with 21 recorded births. The name reached its all-time peak in 2005 with 29 births ranking #3444. Since 1996, the popularity has decreased by 12.5%. In 1998, approximately 1 in every 91,015 boys born was named Thaddaeus. FALLING Recent data shows the name is currently falling.