The Japanese name orochi 大蛇 derives from Old Japanese woröti (with a regular o- from wo- shift, Miller 1971:25-7), but its etymology is enigmatic.
Carr (1990:169) notes that Japanese scholars have proposed "more than a dozen" orochi < woröti etymologies, while Western linguists have suggested loanwords from Austronesian, Tungusic, and Indo-European languages.