| Abbreviation | Definition |
|---|---|
| OCULA | Ontario College and University Library Association |
| OCVE | Organizacin Colegial Veterinaria Espaola |
| OCVE | Organización Colegial Veterinaria Española |
| OCVE | Spanish Veterinary Association |
| ODAS | Orillia and District Agricultural Society |
| ODAS | Orpington and District Archaeological Society |
| ODCS | Old Dominion Chrysanthemum Society |
| ODHS | Old Dominion Humane Society |
| ODHS | Oliver and District Heritage Society |
| ODHS | Ottawa Dental Hygienists Society |
| ODMS | Old Dominion Medical Society |
| ODMS | Old Dominion Military Society |
| ODS | Ohio Dressage Society |
| ODS | Oregon Dental Society |
| ODS | Oregon Dermatology Society |
| ODS | Oregon Dressage Society |
| OE | Ordem dos Engenheiros |
| OE | Society of Engineers |
| OeAW | Austrian Academy of Sciences |
| OeAW | Österreichische Akademie der Wissenschaften |