Eventuallyimitative. Possibly from or influenced by a descendant ofProto-West Germanic*hūō and/orProto-Germanic*uwwilǭ. CompareOld High Germanhūwo,ūvo,(h)ūwila and, as a borrowing into Romance,Catalanòbila, òliba. If so, related to Englishowl. Compare alsoLatinbūbo.
Only seven words in French ending in-ou have their plurals in-oux instead of-ous:bijou,caillou,chou,genou,hibou,joujou,pou.
hibou