Dinosaurs are an animal species that were common on earth during prehistoric times. There are many types of Dinosaurs. Dragons may very well be a type of Dinosaur, or related to them.
The word "dinosaur" doesn't apply to just one species on Earth, but rather several species on Earth and other planets.
The T-Rex in Elevator To Nowhere appeared to be holding Doctor Wells, but in real life it could not be able to hold things.