| ovazione | standing ovation |
| ove | where |
| Over the Hills and Far Away | Over the Hills and Far Away |
| Overclocking | Overclocking |
| Overflow | Arithmetic overflow |
| Overhalla | Overhalla |
| Overhead | Computational overhead |
| Overijssel | Overijssel |
| Overwrite | Squash |
| Overijssel | Overijssel |
| ovest | west |
| Ovest Selvaggio | Wild West |
| Ovestron | Westron |
| Ovide Decroly | Ovide Decroly |
| Ovidio | Ovid |
| Oviedo | Oviedo |
| oviforme | ovoid |
| Ovimbundu | Ovimbundu |
| ovini | ovine |
| oviparo | oviparous |
| Oviraptor philoceratops | Oviraptor |
| Oviraptorosauria | Oviraptorosauria |
| Ovis | Ovis |
| Ovis ammon | Argali |
| Ovis aries | Mutton |
| Ovis canadensis nelsoni | Desert Bighorn Sheep |
| Ovis dalli | Dall Sheep |
| Ovis musimon | Mouflon sheep |
| OVNI | unidentified flying object |
| ovodonazione | egg donation |
| ovoidale | egg-shaped |
| ovolaccio | fly agaric |
| Ovolo | Ovum |
| Ovomaltina | Ovaltine |
| Ovovia | Gondola lift |
| Ovovivipari | Egg |
| OVRA | OVRA |
