Dinosaur

noun

1. In scientific usage, any of the animals belonging to the clade Dinosauria, especially those that existed during the Triassic, Jurassic and Cretaceous periods and are now extinct.
2. In non-scientific usage, any non-avian dinosaur.
3. Any extinct reptile, not necessarily belonging to Dinosauria, that existed between about 230 million and 65 million years ago.
4. A person or organisation that is very old, has very old-fashioned views, or is not willing to change and adapt.
5. Anything no longer in common use or practice.