Where does “ornamentum” come from?

ornamentum (Latin) comes from Latin ornō, from Latin ōrdnō, from Latin ōrdō, from Proto-Italic ored(h)- — to arrange.

Ancestry of “ornamentum”, step by step

Step	Language	Word	Meaning
1	Latin	ornō	—
2	Latin	ōrdnō	—
3	Latin	ōrdō	—
4	Proto-Italic	ored(h)-	to arrange

ornamentum — Etymology, Origin & Word History | Etymology Explorer