Dinosaurs are not lizards, and the man who named them knew it.

Richard Owen was a British comparative anatomist. In July 1841 he presented his work to the British Association, in a lecture that allegedly lasted two hours. The name Dinosauria appeared in print the next year, in his Report on British Fossil Reptiles. Sources split on the date for that reason: Etymonline says 1841, others 1842.

Owen had three fossil animals to work with. Megalosaurus had been described by William Buckland in 1824. Gideon Mantell had described Iguanodon in 1825 and Hylaeosaurus in 1833. The Natural History Museum notes the feature that convinced Owen they belonged together: fused vertebrae at the base of the spine.

He built the name from two Greek words. Sauros means lizard or reptile. Deinos is the interesting half. Wikipedia's article on Owen translates it as "terrible, powerful, wondrous," and Etymonline links it to English "dire."

Schoolbooks usually settle on "terrible lizard." That is not quite what Owen had in mind. The Natural History Museum says he described dinosaurs as "fearfully great," a phrase about their enormous size rather than their teeth. Wikipedia adds that he meant the name also to evoke their size and majesty. It was closer to awe than to fear.

Owen also knew the lizard half was loose. The Museum notes that he recognized these animals as a distinct group, not true lizards. Modern science has pushed them further from lizards still. The fossil record shows that birds are feathered dinosaurs, descended from earlier theropods.

Owen went on to shape how the public saw his creatures. He advised on the life-size dinosaur sculptures at the Crystal Palace in the 1850s, which gave them stocky, mammal-like bodies. He also campaigned to move the British Museum's natural history collections to their own home. The result, the Natural History Museum in South Kensington, opened in 1881.

The word has since grown a second life. Etymonline dates the figurative sense, a person or institution that fails to adapt, to 1952. That meaning gets Owen's word backward. He coined it to praise animals for being magnificent, not to mock them for being extinct.