Where does “ordenlich” come from?

ordenlich (Middle High German) comes from Latin ōrdō, from Proto-Italic ored(h)- — to arrange.

Ancestry of “ordenlich”, step by step

Step	Language	Word	Meaning
1	Latin	ōrdō	a methodical series, arrangement, or order; regular line, row, or series
2	Proto-Italic	ored(h)-	to arrange