Esoterica: What is a gridiron?

With NFL training camps starting next week, and the term "gridiron" about ready to be over-used, it sort of got me thinking....what exactly is a gridiron?

Webster's defines it as: "A football field; so called because of the resemblance of the parallel marked yard lines to a gridiron."

But when I look at the modern football field, I don't necessarily think "a grate for broiling food." The look of the football field has evolved over the years. Hashmarks, for example, weren't around until the 1930s, and goal posts used to look like the letter H and players used to run into them. Sort of an entertaining, yet lost element to the game. Although the modern field looks like a gridiron when observed from above, the original gridiron actually consisted of square grids. Instead of hashmarks and yard markers, the offense would snap the ball in the grid in which it was downed--sort of a violent chess game as a team tried to get out of each square. Hence, the term gridiron was born into the sports lexicon.

The image above shows the classic gridiron from a 1906 game in Ohio between Massillon and Canton. Click on the photo to really get a sense of the old fashion field of play.