| oligarchisch | oligarchic |
| Oligoceen | Oligocene |
| Oligomeer | Oligomer |
| Oligoryzomys | Pygmy rice rat |
| Oligotroof | Oligotrophic |
| olijf | olive |
| Olijfastrilde | Green Avadavat |
| Olijfberg | Mount of Olives |
| olijfboom | olive tree |
| Olijfboomcoalitie | The Olive Tree |
| Olijfbruin waterhoen | Bush-hen |
| Olijffamilie | Oleaceae |
| olijfolie | olive oil |
| olijk | frolic |
| Olimpi Rustavi | FC Olimpi Rustavi |
| Olimpiada Ivanova | Olimpiada Ivanova |
| Olimpija Ljubljana | Olimpija Ljubljana |
| Olin Wilson | Olin Chaddock Wilson |
| Olinda | Olinda |
| Oliveira da Figueira | Minor characters in The Adventures of Tintin |
| Oliveira de Azeméis | Oliveira de Azeméis |
| Oliveira de Frades | Oliveira de Frades |
| Oliveira do Hospital | Oliveira do Hospital |
| Olivenza | Olivenza |
| Oliver | Oliver |
| Oliver Bierhoff | Oliver Bierhoff |
| Oliver Chesler | The Horrorist |
| Oliver Cromwell | Oliver Cromwell |
| Oliver Hardy | Oliver Hardy |
| Oliver Heaviside | Oliver Heaviside |
| Oliver Hirschbiegel | Oliver Hirschbiegel |
| Oliver Kahn | Oliver Kahn |
| Oliver Kovačević | Oliver Kovačević |
| Oliver Lodge | Oliver Joseph Lodge |
| Oliver Mtukudzi | Oliver Tuku Mtukudzi |
| Oliver Neuville | Oliver Neuville |
| Oliver Norvelle Hardy | Oliver Norvelle Hardy |
| Oliver Riedel | Oliver Riedel |
| Oliver Sacks | Oliver Sacks |
| Oliver Stone | Oliver Stone |
| Oliver Tambo | Oliver Tambo |
| Olivera Jevtić | Olivera Jevtić |
| Oliverio Rincon | Oliverio Rincón |
| Olivia de Havilland | Olivia de Havilland |
| Olivia Lewis | Olivia Lewis |
| Olivia Newton-John | Olivia Newton-John |
| Olivier Besancenot | Olivier Besancenot |
| Olivier Blunder | Achille Talon |
| Olivier Grouillard | Olivier Grouillard |
| Olivier Levasseur | Olivier Levasseur |
| Olivier Messiaen | Olivier Messiaen |
| Olivier Panis | Olivier Panis |
| Olivier Plunkett | Oliver Plunkett |
| Olivier Schoenfelder | Olivier Schoenfelder |
| Olivier van Noort | Olivier van Noort |
| Olivijn | Olivine |
| oliën | grease |
| Oljokma | Olyokma River |
| Oljokminsk | Olyokminsk |
| Olkusz | Olkusz |
| Ollastra | Ollastra Simaxis |
| Ollersdorf im Burgenland | Ollersdorf im Burgenland |
| Olli Rehn | Olli Rehn |
| Ollie | Ollie |
| Ollon | Ollon |
| Ollotis alvaria | Colorado River Toad |
| olm | elm |
| Olmeken | Olmec |
| Olof I van Zweden | Olof Björnsson |
| Olof II van Zweden | Olof Skötkonung |
| Olof Palme | Olof Palme |
| Olof Vilhelm Arrhenius | Olof Vilhelm Arrhenius |
| Olofström | Olofström Municipality |
| Oloid | Oloid |
| Olomouc | Olomouc |
| Olonets | Olonets |
| Olongapo City | Olongapo City |
| Olpe | Olpe |
| OLS Oulu | Oulun Luistinseura |
| Olsbrücken | Olsbrücken |
| Olsen Brothers | Olsen Brothers |
| Olsztyn | Olsztyn |
| Olsztynek | Olsztynek |
| Olszyna | Olszyna |
| Olt | Olt River |
| Oltcit | Oltcit |
| Olten | Olten |
| Oltenië | Oltenia |
| Oltingen | Oltingen |
| Olusegun Obasanjo | Olusegun Obasanjo |
| Olybrius | Olybrius |
| Olympia Dukakis | Olympia Dukakis |
| Olympia-Stadion | Olympia-Stadion |
| olympiade | olympiad |
| Olympiakos Nicosia | Olympiakos Nicosia |
| Olympiakos Piraeus | Olympiacos FC |
| Olympias | Olympias |
| Olympiastadion | Olympic Stadium |
| Olympic | Olympic |
| Olympic Airlines | Olympic Airlines |
| Olympic Oval | Olympic Oval |
| Olympique Béja | Olympique Béja |
| Olympique Khouribga | Olympique Khouribga |
| Olympique Lyonnais | Olympique Lyonnais |
| Olympique Marseille | Olympique de Marseille |
| Olympique Nîmes | Nîmes Olympique |
| Olympique Safi | Olympique Safi |
| Olympisch | Olympic |
