The family Iguanodontidae comprises a group of ornithopod dinosaurs that lived from the Early Jurassic to Late Cretaceous periods. The term Iguanodontidae means "iguana-toothed family" and refers to their tooth shape, which is similar to that of modern-day iguanas. However, there are several synonyms that have been proposed for this family name, including the names Hadrosauridae and Styracosterna. Hadrosauridae means "bulky lizards family," and Styracosterna means "spike-backed chest family." These names refer to the physical characteristics of the dinosaurs within this family, which were often characterized by large size, a bulky build, and distinct spikes or plates on their backs.