| Ogg Media | Ogg Media |
| Ogham | Ogam |
| Ogre County | Ogres distrikt |
| Ogre District | Ogres distrikt |
| Ohio | Ohio |
| Ohio River | Ohiofloden |
| Ohio Wesleyan University | Ohio Wesleyan University |
| ohm | ohm |
| Ohm River | Ohm |
| Ohm's law | Ohms lov |
| Ohne | Udder |
| Ohrid | Ohrid |
| Ohrid municipality | Ohrid |
| Oidipus complex | Ødipuskompleks |
| Oidium | Meldug |
| Oignon | Løg |
| Oikoumene | Økumene |
| oil | olie |
| oil and fat industry | fedtstofindustrien |
| oil binding agent | stabilisator til olie |
| oil boom | oliespærre |
| Oil crisis | Oliekrise |
| oil disaster | olieudslip |
| oil exploration | olieefterforskning |
| oil extraction | olieudvinding |
| Oil flow meter | Flowmåler |
| Oil man | Supertanker |
| Oil of olives | Olivenolie |
| Oil painting | Olie |
| oil pipeline | olierørledning |
| Oil platform | Olieboreplatform |
| oil pollution | olieforurening |
| oil pollution abatement | bekæmpelse af olieforurening |
| oil production | oliefremstilling |
| Oil quality | Olie |
| oil recovery vessel | oprensningsfartøj til oliespild |
| oil refinery | olieraffinaderi |
| Oil reserves | Beviste oliereserver |
| oil residue recuperation | genindvinding af olierester |
| oil slick | olieforurening til havs |
| oil spill | olieudslip |
| oil tanker | olietankskib |
| oil-based energy | oliebaseret energi |
| Oil-for-Food Programme | Olie-for-mad-programmet |
| Ointment | Sovs |
| Oise | Oise |
| Oise River | Oise |
| Ojos del Salado | Ojos del Salado |
| OK | godt |
| Okapi | Okapi |
| okay | god |
| OKG | Oskarshamn kernekraftværk |
| Okhaldhunga District | Okhaldhunga District |
| Okinawa Island | Okinawa |
| Okinawa Prefecture | Okinawa |
| Oklahoma | Oklahoma |
| Oklahoma City | Oklahoma City |
| Oksana Akinshina | Oksana Akinsjina |
