The World Trade Center site is referred to as Ground Zero due to its significance as the location where the original World Trade Center complex was destroyed in the terrorist attacks of September 11, 2001. The term "ground zero" is commonly used to refer to the epicenter or point of origin of a major disaster or explosion. In the context of the World Trade Center, the term has become associated with the site of the attacks and is often used as a shorthand reference to the location.