Terminology
The term "gridiron" in reference to football first developed in the United States. It originally referred to the sport's playing field, alternately known as the "grid", due to the its patterned markings which give it the appearance of a gridiron. The terms "gridiron" and "grid" were thence applied loosely to the game itself.
Especially outside of the U.S. and Canada, the terms "gridiron" and "gridiron football" are often used to distinguish the North American sport from other codes of football. "Gridiron" is particularly common in Australia and New Zealand. In some cases the terms are used specifically for American football, sometimes even in distinction from Canadian football, though it is now often used as a blanket term for all North American variants.
Read more about this topic: Gridiron Football