Order Saurischia, which refers to a group of dinosaurs with lizard-like hips, has several synonyms. One of the most common synonyms is "lizard-hipped dinosaurs." Other synonyms for this order include "Saurischian dinosaurs," "Saurischa," and "Saurischiformes." The term "Saurischia" comes from the Greek words "sauros" (meaning lizard) and "ischion" (meaning hip bone). It was coined in the 19th century by paleontologist Richard Owen. Saurischian dinosaurs include some of the most well-known dinosaurs, such as the mighty Tyrannosaurus rex and the massive long-necked sauropods. These dinosaurs dominated the planet for millions of years before becoming extinct around 65 million years ago.