Where does “ō-” come from?

ō- (Old Swedish) comes from Old Norse ú-, from Proto-Germanic un-, from Proto-Indo-European n̥-, from Proto-Indo-European ne — not.

Ancestry of “ō-”, step by step

StepLanguageWordMeaning
1Old Norseú-not, non-, un-
2Proto-Germanicun-not, un-
3Proto-Indo-Europeann̥-not, un-
4Proto-Indo-Europeannenot

Words derived from “ō-”

Every word from Proto-Indo-European ne →Every word from Proto-Indo-European n̥- →Every word from Proto-Germanic un- →