An "iron griddle" is a flat, heavy cooking surface made of iron. It is often used to cook food like pancakes or burgers on a stove or grill. Full definition
As you can see in the (terrible) photo below, I cooked these in a cast iron griddle pan on the stove, but you can also cook them up on the barbecue to great effect. (family-friends-food.com)
Heat a large nonstick pan or cast - iron griddle over medium heat and brush with some melted butter. (foodnetwork.com)
Set a large cast - iron griddle on the grill to heat or place a pizza pan in the oven and preheat to 500 °F. (epicurious.com)