dinosaur

Short definition from Wiktionary

Noun

1. 1
   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. 2
   Any member of the clade Dinosauria other than birds.
3. 3
   Any extinct reptile, not necessarily belonging to Dinosauria, that existed between about 230 million and 65 million years ago, as well as the stem-mammal Dimetrodon.
4. 4
   Something or someone that is very old or old-fashioned, or is not willing to change and adapt.
5. 5
   Anything no longer in common use or practice.