Pachycephalous

Part of speech: adjective

Definitions

1. Having an unusually thick or heavy skull, a trait notably found in certain dinosaurs and bone-headed animals
2. Describing a creature whose cranium is abnormally thick, as in some dome-headed dinosaur species
3. Characterized by a massively thickened skull bone, often used in paleontology to describe certain extinct reptiles

Etymology: Pachycephalous describes an animal, usually a bird or a dinosaur, with an unusually thick skull, and it was coined in the 19th century from two Greek roots: "pachys" (thick) and "kephalē" (head). Because the words are built from classical Greek parts, the term is a modern scientific formation, not something ancient Greek speakers used. It appears in zoological and palaeontological writing, where it helped describe skull shapes that were otherwise hard to name precisely. The word's most famous application is to dinosaurs in the family Pachycephalosauridae, the "thick-headed lizards," whose domed skulls may have been used in head-butting contests. Its "-ous" ending is the standard English adjective suffix, which attaches to Greek-derived nouns much as "-ous" does in words like "famous" and "nervous."

Synonyms: thick-skulled