Where does “pachycephalosaur” come from?

pachycephalosaur (English) comes from Translingual Pachycephalosaurus, from Translingual -saurus, from Ancient Greek σαῦρος, from Ancient Greek σαύρα — lizard.

pachycephalosaur (English): Any of a group of herbivorous dinosaurs, of the genus Pachycephalosaurus from the late Cretaceous period

Definitions

Any of a group of herbivorous dinosaurs, of the genus Pachycephalosaurus from the late Cretaceous period

Ancestry of “pachycephalosaur”, step by step

Step	Language	Word	Meaning
1	Translingual	Pachycephalosaurus	genus\|a dinosaur that lived during the Late Cretaceous period (Maastrichtian faunal stage) of what is now North America}} Currently contains only the species †Pachycephalosaurus wyomingensis
2	Translingual	-saurus	Forms genus names of lizards; Forms genus names...
3	Ancient Greek	σαῦρος	Alternative form of σαύρᾱ; horse mackerel
4	Ancient Greek	σαύρα	lizard

Every word from Ancient Greek σαύρα →Every word from Ancient Greek σαῦρος →Every word from Translingual -saurus →