Where does “óchtar” come from?

óchtar (Old Irish) comes from Proto-Celtic ouxsterom, from Proto-Indo-European h₃ewp-s- — high.

óchtar (Old Irish): top, surface, cream

Definitions

Step	Language	Word	Meaning
1	Proto-Celtic	ouxsterom	—
2	Proto-Indo-European	h₃ewp-s-	high

óchtar — Etymology, Origin & Word History | Etymology Explorer