Handball is called Team Handball in the U.S. to distinguish it from another sport called handball which is more well known. This Handball is played with a small rubber ball and is a 1 on 1 or 2 on 2 game that involves players slapping the ball with their hands off a wall. This “wall handball” is played throughout the United States and has a much higher name recognition than the Handball played in Europe and other parts of the world. Referring to Handball as simply Handball in the United States therefore often leads to confusion because most people are only familiar with wall handball.
To distinguish the sport from “Wall Handball” the name Team Handball was adopted. Wall Handball is also played in other parts of the world including Ireland and Canada. To differentiate the sports in those countries, Handball is often referred to as Olympic Handball in Ireland and in Anglophone Canada the sport is sometimes called European Team Handball (ETH).
Wikipedia article on Wall Handball: Link
Wikipedia disambiguation discussion on Handball: Link (Semantic problems are also difficult for Wikipedia to solve)