| Abbreviation | Definition |
|---|---|
| OPEC | Orange Pineapples Enter Contests |
| OPEC | Ordinary People Expecting Change |
| OPEC | Organization Of People For Energy Conservation |
| OPEC | Organization of Preppies that Eat Cheese |
| OPEC | Overflowing Porta-potties Excrete in China |
| OPEC | Overly Protective Egyptian Caskets |
| OPEL | Old People Ending Lives |
| OPH | Old People Humor |
| OPM | Other People's Money |
| OPM | Our Peoples' Money |
| OPML | Other Peoples' Markup Language |
| OPP | Official Party Poopers |
| OPW | Old People Weed |
| OQD | Other Quack Doctor |
| ORACLE | One Rich A** Called Larry Ellison |
| ORACLE | One Rich Arshole Called Larry Ellison |
| ORWD | Our Rage Won’t Die |
| OS | Old Shinola |
| OS/2 | Obsolete Soon, Too |
| OSA | Orangutans Seem Alert |