| Abbreviation | Definition |
|---|---|
| OCG | Old Chinese Guy |
| OCPD | Obsessive Compulsive Potter Disorder |
| OCR | Obsessive Compulsive Recluse |
| OCR | Obsolete Card Reader |
| OD | Open Doors |
| OD | Orange Duck |
| OD | Order of Disorder |
| ODC | Other Dumb Cluck |
| ODCT | Odd Discrete Cosine Transform |
| ODD | Obsessive Derek Disorder |
| ODM | Original, Dynamic, and Minimal |
| ODM | Other Dumb Machine |
| ODQ | Other Dumb Questions |
| ODS | One Damn Sheep |
| OEC | Odd Engineering Contraption |
| OEC | Only Envying Clowns |
| OECD | Organization For Economic Coercion and Direction |
| OED | Oneism Exercised Daily |
| OEM | Outside the Empire of Microsoft |
| OFA | Onafhankelijke Fanclub Ajax |