| OA | Predicate.Util, Predicate |
| OAB | Predicate.Util, Predicate |
| OAN | Predicate.Util, Predicate |
| OColor | Predicate.Util, Predicate |
| oColor | Predicate.Util, Predicate |
| OctetRE | Predicate.Examples.Common |
| Odd | Predicate.Prelude, Predicate |
| ODebug | Predicate.Util, Predicate |
| oDebug | Predicate.Util, Predicate |
| ODisp | Predicate.Util, Predicate |
| oDisp | Predicate.Util, Predicate |
| OEmpty | Predicate.Util, Predicate |
| Ok | Predicate.Examples.Refined3 |
| ok | Predicate.Examples.Refined3 |
| OkNot | Predicate.Examples.Refined3 |
| oknot | Predicate.Examples.Refined3 |
| OkNotR | Predicate.Examples.Refined3 |
| OkR | Predicate.Examples.Refined3 |
| OL | Predicate.Util, Predicate |
| OMsg | Predicate.Util, Predicate |
| oMsg | Predicate.Util, Predicate |
| OneP | Predicate.Prelude, Predicate |
| Ones | Predicate.Prelude, Predicate |
| ONoColor | Predicate.Util, Predicate |
| oNoColor | Predicate.Util, Predicate |
| OOther | Predicate.Util, Predicate |
| oOther | Predicate.Util, Predicate |
| OptT | Predicate.Util, Predicate |
| OptTC | Predicate.Util, Predicate |
| OrA | Predicate.Prelude, Predicate |
| OrdA | Predicate.Prelude, Predicate |
| OrdA' | Predicate.Prelude, Predicate |
| OrderingP | Predicate.Util, Predicate |
| OrdI | Predicate.Prelude, Predicate |
| OrdP | Predicate.Prelude, Predicate |
| ORecursion | Predicate.Util, Predicate |
| oRecursion | Predicate.Util, Predicate |
| Ors | Predicate.Prelude, Predicate |
| OrT | Predicate.Util, Predicate |
| OU | Predicate.Util, Predicate |
| OUB | Predicate.Util, Predicate |
| OWidth | Predicate.Util, Predicate |
| oWidth | Predicate.Util, Predicate |
| OZ | Predicate.Util, Predicate |