| orientamento | orientation |
| orientamento sessuale | sexual orientation |
| orientare | position |
| orientarsi | orientate |
| Oriente | Orient |
| orificio | orifice |
| orifizio | opening |
| Origa | Origa |
| origami | origami |
| Origami modulare | Modular origami |
| origano | oregano |
| Origanum vulgare | Oregano |
| Origene Adamantio | Origen |
| Original Amiga chipset | Amiga Original chipset |
| Original anime video | Original video animation |
| Original Design Manufacturer | Original design manufacturer |
| Original net animation | Original net animation |
| originale | different |
| originalità | oddness |
| originare | originate |
