| Oceania | Oceania |
| Oceania Football Confederation | Oceania Football Confederation |
| Oceania lontana | Remote Oceania |
| Oceania vicina | Near Oceania |
| oceanico | oceanic |
| Oceanine | Oceanid |
| oceano | sea |
| Oceano Antartico | Antarctic Ocean |
| Oceano Artico | Arctic Ocean |
| Oceano Atlantico | Atlantic Ocean |
| Oceano Indiano | Indian Ocean |
| Oceano nord Atlantico | North Atlantic Ocean |
| Oceano Pacifico | Pacific |
| Oceano Tetide | Tethys Ocean |
| oceanografa | oceanographer |
| oceanografia | oceanography |
| Oceanografia chimica | Chemical oceanography |
| oceanografo | oceanographer |
| Oceanário di Lisbona | Lisbon Oceanarium |
| ochetta | gosling |
| Ochlenberg | Ochlenberg |
| Ochotsk | Okhotsk |
| Ochsenfurt | Ochsenfurt |
| Ochsenhausen | Ochsenhausen |
| Ocimum | Ocimum |
| Ocimum basilicum | Basil |
| Ockelbo | Ockelbo Municipality |
| Ocniţa | Raionul Ocniţa |
| Ocquier | Ocquier |
| ocra | ocher |
| Ocra rossa | Red ochre |
| Ocratossina | Ochratoxin |
| Ocrida | Ohrid |
| OCT | Oct |
| Octave Mirbeau | Octave Mirbeau |
| Octaver | Octave effect |
| Octavio Lepage Barreto | Octavio Lepage |
| Octavio Paz | Octavio Paz |
| Octobasso | Octobass |
| Octopus | Octopus |
| Octopus vulgaris | Octopus |
| oculare | ocular |
| Oculare di Kellner | Kellner eyepiece |
| Oculare di Ramsden | Ramsden eyepiece |
| Oculari | Eyepieces |
| Oculari ortoscopici | Orthoscopic eyepiece |
| oculato | cautious |
| oculavezza | circumspection |
| oculista | ophthalmologist |
| oculistica | ophthalmology |
| od | or |
| Oda Nobunaga | Oda Nobunaga |
| Odaiba | Odaiba |
| Odalismo | Odalism |
| Odate | Odate |
| Odawa | Ottawa |
| ODBC | Open Database Connectivity |
| Odda | Odda |
| Oddantonio II da Montefeltro | Oddantonio da Montefeltro |
| Oddo | Otto |
| Oddone da Cluny | Odo of Cluny |
| Oddone di Saint Amand | Odo de St Amand |
| Oddone di Savoia | Otto of Savoy |
| Oddone I di Tolosa | Odo of Toulouse |
| Oddone II di Guascogna | Odo of Gascony |
| ode | ode |
| Odelzhausen | Odelzhausen |
| Odense | Odense |
| Odense Boldklub | Odense Boldklub |
| Odenwald | Odenwald |
| Odenwaldkreis | Odenwaldkreis |
| Oder | Oder River |
| Oder-Spree | Oder-Spree |
| Oderberg | Oderberg |
| Odessa | Odessa |
| Odetta | Odetta |
| Odi di Salomone | Odes of Solomon |
| odiabile | hateful |
| odiare | hatred |
| odiare dal più profondo del cuore | detest from the bottom of one's heart |
