What is an iguanodon?

A dinosaur that lived long ago. :)

Answer2: The ornithischians ("bird hipped") were one of two general classes of dinosaurs as determined by the structure of their hips. Those in this category had a hip structure similar to that of a bird but, of course, vastly larger. Some were small in overall size, others huge. The iguanodon reached lengths of 30 feet [9 m]