Allosaurus (IPA: ) was a large (up to 9.7 m long) bipedal carnivorous dinosaur. The name Allosaurus comes from the Greek allos/αλλος, meaning 'strange' or 'different' and saurus/σαυρος, meaning 'lizard' or 'reptile'. It was named 'different lizard' because its vertebrae were different from those of other dinosaurs known at the time of its discovery.