Where does “rehhanōn” come from?

rehhanōn (Old High German) comes from Proto-Germanic rekanōną, from Proto-Indo-European h₃reǵ- — to straighten, to right oneself; right; just.

Ancestry of “rehhanōn”, step by step

Step	Language	Word	Meaning
1	Proto-Germanic	rekanōną	to count; to explain
2	Proto-Indo-European	h₃reǵ-	to straighten, to right oneself; right; just

rehhanōn — Etymology, Origin & Word History | Etymology Explorer