Richard Owen created Dinosauria from Greek deinos and sauros. Its components describe a formidable lizard, rather than simply an ancient animal. Scientific naming often makes new labels out of very old linguistic material.
The literal name reflects the historical naming choice, not modern classification: dinosaurs are not lizards.
Sources
- Merriam-Webster · dinosaur
Dictionary word history; the component and historical references below supply additional detail.
- Online Etymology Dictionary · dinosaur
Historical forms, meanings, and context for the route described here.