Where does “deksteros” come from?

deksteros (Proto-Italic) comes from Proto-Indo-European deḱs(i)-tero-, from Proto-Indo-European deḱs- — right.

Ancestry of “deksteros”, step by step

Step	Language	Word	Meaning
1	Proto-Indo-European	deḱs(i)-tero-	—
2	Proto-Indo-European	deḱs-	right

deksteros — Etymology, Origin & Word History | Etymology Explorer