| ondeggiare | sway |
| Ondina | Ondine |
| Ondina Valla | Trebisonda Valla |
| Ondo | Ondo State |
| ondoso | billowy |
| ondulare | crimp |
| ondularsi | wave |
| ondulato | curled |
| ondulatorio | undulated |
| ondulazione | wave |
| ondulazione permanente | perm |
| Ondárroa | Ondárroa |
| One | One Railway |
| One Day in Your Life | One Day in Your Life |
| One Hour Photo | One Hour Photo |
| One laptop per child | One Laptop per Child |
| One Man Army and the Undead Quartet | One Man Army and the Undead Quartet |
| One Piece | One Piece |
| One Tree Hill | One Tree Hill |
| One Wild Oat | One Wild Oat |
| One-Two-GO Airlines | One-Two-GO Airlines |
| Onega | Onega |
| Oneglia | Oneglia |
| Oneida | Oneida |
| Oneiroi | Oneiroi |
| Onel de Guzmán | ILOVEYOU |
| Oneonta | Oneonta |
