English abbreviations from ohu to oilrig
- OHU (OHio University (non-standard, usually OU))
- OHW (Old Home Week)
- OHWS (Offensive Hand Weapon System)
- OI (Oxygen Index)
- OI&A (Office of Intelligence and Analysis (DHS))
- OIBUA (Operations In Built-Up Areas)
- OIC (Officer In Charge)
- OICC (Officer In Charge of Construction)
- OICD (Optometric Institute and Clinic of Detroit)
- OICU (Oklahoma Independent Colleges and Universities)
- OICW (Objective Individual Combat Weapon)
- OID (Object Identifier)
- OIDMTC (Ontario Interactive Digital Media Tax Credit)
- OIE (World Organisation for Animal Health (originally the Office international des épizooties, French for "International Epizootic Office"))
- OIF (Operation Iraqi Freedom)
- OIG (Office of Inspector General)
- OIH (Ohio Industries for the Handicapped)
- OII (Oxford Internet Institute)
- OIIT (Office of Informational and Instructional Technology)
- OIK (Organisation für Internationale Kontakte / Organization for International Contacts)
- OIL (Ontology Interchange Language)
- OILRIG (Oxidation Is Losing, Reduction Is Gaining)
