Thaddaeus is a distinctive boys' name in United States, ranking #4514 in 1999 with 16 recorded births. The name reached its all-time peak in 2005 with 29 births ranking #3444. Since 1996, the popularity has decreased by 33.3%. In 1999, approximately 1 in every 120,005 boys born was named Thaddaeus. FALLING Recent data shows the name is currently falling.