What is a dinosur?

Dinosaurs were reptiles that lived 245 to 65 million years ago. Some ate plants, some ate meat, lots ate each other. They are not lizards, even though the name dinosaur means terrible lizard. They could not fly or live in the water (so pterodatyls, plesiOSaurs, icthyosaurs, etc were not dinosaurs). They varied greatly in size, some were longer than tennis courts, some were no taller than your knee.