The Spanish word 'dinosaurio' comes from Latin 'dinosaurium', which was formed from 'dinosaurus' with the Latin noun suffix '-ium'. The term 'dinosaurus' itself was constructed from two Ancient Greek words: 'deinos' (δεινός) meaning 'terrible' and 'sauros' (σαῦρος) meaning 'lizard'. Thus, the etymology literally translates to 'terrible lizard'.

This scientific term was coined in the 1840s by paleontologist Richard Owen to describe these ancient reptiles, and the word has since been adapted into many languages, including Spanish.

While 'dinosaurio' itself is a commonly used word in Spanish, you might encounter related words like 'saurio' (meaning 'saurian' or 'lizard-like'), which comes from the same Greek root 'sauros'.

The English word 'dinosaur' is a direct cognate of 'dinosaurio', sharing the exact same Greek origins. Other related English words include 'dinosaurian' (relating to dinosaurs) and various terms ending in '-saurus' like 'tyrannosaurus' or 'brontosaurus'. The prefix 'dino-' is also used in English words like 'dinoflagellate', while the element '-saur' appears in words like 'ichthyosaur'.