Richard Owen is known for coining the term Dinosauria in 1842. He did so after studying the remains of what were then known as Iguanodon and Megalosaurus, which he believed were related. He chose the name Dinosauria from the Greek words deinos (terrible) and sauros (lizard), to reflect his belief that they were fearsome creatures.
The Remarkable Legacy of Richard Owen: An Engaging Quiz on the English Biologist and Paleontologist