dinosaur

Noun

dinosaur (plural dinosaurs)

1. (usually) Those animals of the clade Dinosauria that existed during the Triassic, Jurassic and Cretaceous periods and are now extinct.
   • Despite what some cartoons portray, no humans were around when dinosaurs roamed the Earth.

   Synonyms:

   non-avian dinosaur

2. (less often but also correctly) Any of the animals belonging to the clade Dinosauria, including its sole surviving lineage: Neornithes.
   • Many people love their backyard birds, but some of us may not realize that those feathery friends are also literally dinosaurs, in a biologically accurate sense of that word.
3. (broadly, informal, proscribed) 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.
   • Pterosaurs, plesiosaurs, icthyosaurs — I don't know, they're all dinosaurs to me!
   • "Not a bird, my dear Roxton - not a bird." "A beast?" "No; a reptile - a dinosaur."1912, Arthur Conan Doyle, The Lost World […], London; New York, N.Y.: Hodder and Stoughton, →OCLC
4. (colloquial, figuratively) Someone or something that is very old or old-fashioned, especially someone who is not willing to change and adapt.
   • She may be a tough old bird, but it's a mistake to write her off as a dinosaur; you do so at your own risk.
   • [The OS/360 linkage editor] is the culmination of years of development of static overlay technique. Yet it is also the last and finest of the dinosaurs, for it belongs to a system in which multiprogramming is the normal mode and dynamic core allocation the basic assumption.1975, Frederick P. Brooks Jr., The Mythical Man-Month, published 1995

   Synonyms:

   fossil, old fart, fuddy-duddy

5. (colloquial, figuratively) Anything no longer in common use or practice.
   • I couldn't believe it when I saw the equipment that they were still using. Those machines were all dinosaurs, but they were busily cranking out production.