noun

• (sciences) Any of the animals belonging to the clade Dinosauria, especially those that existed during the Triassic, Jurassic and Cretaceous periods and are now extinct.
• (colloquial) Any member of the clade Dinosauria other than birds.
• (proscribed) Any extinct reptile, not necessarily belonging to Dinosauria, that existed between about 230 million and 65 million years ago.
• (figuratively, colloquial) Something or someone that is very old or old-fashioned, or is not willing to change and adapt.
• (figuratively, colloquial) Anything no longer in common use or practice.