The name can have two different etymologies, the most obvious, pronounced (TAHZH) is from the Arabic word for crown as in the Taj Mahal. Another source, pronounced (TYE) is from the Scandianavian diminutive form of Tage.
In recent years, its Arabic form became somewhat popular outside the Islamic world in Australia and the United States, among people of various ethnic backgrounds. In Australia, Taj made an appearance in the Top 100 in 2008, coming in as the 89th most popular male name. In the United States, Taj only appeared in the U.S. Top 1000 2 times, in 1976 and again in 1998, peaking at a meager #952 in 1998.
The Scandianvian Taj currently ranks as the 64th most popular male name in Slovenia (2016).