Why are dinosaurs called terrible lizards?

Dinosaur means "terrible lizard," and the phrase is older than any theme park. In 1842 the British anatomist Sir Richard Owen grouped Megalosaurus, Iguanodon, and Hylaeosaurus as Dinosauria. He built the word from Greek deinos (δεινός), which covers terrible, potent, and fearfully great, and sauros (σαῦρος), a lizard or reptile. An Oxford University Museum of Natural History essay on the archive uses the same year and glosses deinos as fearfully great. Owen was talking about size and majesty, not only about monsters.

Greek roots, Latin clothing

People ask for the Latin because scientific names look Latin. These two parts are Greek. Owen was writing in the tradition that turns Greek roots into a Latinized scientific word. If a worksheet asks "what is terrible lizard in Latin," the fair answer is that the famous phrase is a translation of Dinosauria, not a line from a Roman author. I am not inventing a Latin motto to satisfy the worksheet.

Other names are other animals

If you came here because a 2026 game is also called Terrible Lizards, that title is a pun on this phrase and on a fictional Route 66 attraction called Dalton's Dinos. The game is a first-person horror parkour story released on 29 Oct 2026. It is not a museum label, and this page is not its manual. The terminal home and the wiki are there when you want the game. The podcast and the 1990s cartoon that use similar names are sorted on the disambiguation page.