Where does “Megaceros” come from?

Megaceros (Translingual) comes from Translingual mega-, from Ancient Greek μέγας, from Proto-Indo-European meǵh₂s — great.

Ancestry of “Megaceros”, step by step

Step	Language	Word	Meaning
1	Translingual	mega-	Used with taxon names to form other taxon names,...
2	Ancient Greek	μέγας	big, large; great, mighty, loud; marvelous,...
3	Proto-Indo-European	meǵh₂s	great

Megaceros — Etymology, Origin & Word History | Etymology Explorer