Tadeo is the Spanish form of Thaddeus, the name of one of the twelve apostles, of uncertain origin and usually explained as "heart" or "courageous" from Aramaic. The animated Spanish film Tad, the Lost Explorer (Tadeo Jones, 2012) made it a hit with Spanish-speaking families. Tadeo was unknown in the United States in 2000, entered the top 1000 in 2016 and has climbed to number 427 in 2025.