Index - O
| odd | Bio.Prelude |
| off | Bio.Iteratee.Builder |
| OldDamage | Bio.Adna |
| on | Bio.Prelude |
| onException | Bio.Prelude |
| openFd | Bio.Prelude |
| OpenFileFlags | |
| 1 (Data Constructor) | Bio.Prelude |
| 2 (Type/Class) | Bio.Prelude |
| OpenMode | Bio.Prelude |
| OpenPunctuation | Bio.Prelude |
| openTwoBit | Bio.TwoBit |
| optional | Bio.Prelude |
| or | Bio.Prelude |
| Ord | Bio.Prelude |
| ord | Bio.Prelude |
| Ordering | Bio.Prelude |
| Ordering' | Bio.Iteratee, Bio.Bam |
| orElse | Bio.Prelude |
| OtherError | Bio.Prelude |
| otherExecuteMode | Bio.Prelude |
| OtherLetter | Bio.Prelude |
| otherModes | Bio.Prelude |
| OtherNumber | Bio.Prelude |
| OtherPunctuation | Bio.Prelude |
| otherReadMode | Bio.Prelude |
| OtherSymbol | Bio.Prelude |
| otherwise | Bio.Prelude |
| otherWriteMode | Bio.Prelude |
| Overflow | Bio.Prelude |
| overlaps | Bio.Bam.Regions |
| ownerExecuteMode | Bio.Prelude |
| ownerModes | Bio.Prelude |
| ownerReadMode | Bio.Prelude |
| ownerWriteMode | Bio.Prelude |