| German | English |
| Operationsverstärker {m} | computing amplifier |
| Operationsteil {m} | operations code |
| Operationstisch {m} | operating table |
| Operationsschwester {f} OP-Schwester {f} | theatre sister [Br.] operating-room nurse [Am.] |
| Operator {m} [math.] | operator |
| Operatornorm {f} [math.] | operator norm |
| Operette {f} [mus.] | operetta |
| Opernball {m} | opera ball |
| Opfer {n} | immolation |
| Opfer {n} | oblation |
| Opfer {n} Opferung {f} Aufopferung {f} | Opfer {pl} Opferungen {pl} Aufopferungen {pl} | sacrifice | sacrifices |
| Opfer {n} Schlachtopfer {n} | Opfer {pl} Schlachtopfer {pl} | victim | victims |
| Opfer {n} Angebot {n} | offering |
| Zum-Opfer-Werden {n} | victimization |
| als Opfer aussuchen | to prey (on) |
| Opferer {m} | Opferer {pl} | sacrificer | sacrificers |
| Ophtalmatica {pl} | ophtalmic drugs |
| Opiat {n} | opiate |
| Opium {n} | opium |
| Opossum {n} | possum |
| Opportunismus {m} | Opportunismen {pl} | opportunism | opportunisms |
| Opportunist {m} | Opportunisten {pl} | opportunist | opportunists |
| Opportunist {m} | Opportunisten {pl} | timeserver | timeservers |
| Opposition {f} | der Opposition angehören | in Opposition | opposition | to be in opposition | anti |
| Mitglied der Opposition | oppositionist |
| Oppositionelle {m,f} Oppositioneller | member of the opposition |
| Oppositionspartei {f} | opposition party |
| Opposition {f} | outs |
| Optik {f} | optics |
| Optiker {m} Optikerin {f} | Optiker {m} | optician | opticians |
| Optiklabor {n} | optics laboratory |
| Optimalbereich {m} | rated range |
| Optimalprogramm {n} | optimally coded program |
| Optimierer {m} | optimizer |
| Optimierung {f} | optimation |
| Optimierung {f} [math.] | Optimierungen {pl} | lineare Optimierung {f} | nichtlineare Optimierung {f} | optimization | optimizations | linear optimization | non-linear optimization |
| Optimismus {m} | optimism |
| Optimist {m} | Optimisten {pl} | optimist | optimists |
| Optimum {n} | optimum |
| Optimum {n} | optimal |
| Option {f} | Optionen {pl} | Option am Geld | Option verfallen lassen | option | options | at-the-money option | to allow an option to lapse |
| Optionsaufgabe {f} | abandonment of option |
| Optionspreis {m} | at the money |
| Optoelektronik {f} | optoelectronics |
| Optokoppler {m} | optical coupler optocoupler |
| Optometer {n} | optometrist |
| Optometrie {f} | optometry |
| Opus {m} | opuses |
| Orakel {n} | oracle |
| Orange {n} | Orangen {pl} | orange | oranges |
| Orangeade {f} [cook.] | orangeade |
| Orangeat {n} [cook.] | candied orange peel |
| Orangenbaum {m} [bot.] | orange |
| Orangengebäck {n} [cook.] | orange cookies |
| Orangenlikor {m} [cook.] | orange liqueur |
| Orangennscheibe {f} | twist of orange |
| Orangensaft {m} Apfelsinensaft {m} [cook.] | orange juice |
| Orangenschale {f} [cook.] | orange peel |
| Orangenschalenstruktur {f} | orange-peel texture |
| Oratorium {n} | oratorio |
| Orchester {n} | Orchester {pl} | orchestra | orchestras |
| Orchesterraum {m} Orchestergraben {m} | orchestra pit |
| Orchestersitze {pl} | orchestra stalls |
| Orchidee {f} [bot.] | orchid |
| Orden {m} | Orden {pl} | jdm. einen Orden für etw. verleihen | einen Orden bekommen | Orden tragen | medal decoration | medals decorations | to decorate sb. for sth. | to be decorated to receive a decoration | to wear one's decorations |
| Orden {m} Glaubensorden {m} | order holy order |
| Ordensgelübde {n} | monastic vows |
| Ordensschwester {f} | nun |
| Orderscheck {m} | order cheque |
| Orderschuldverschreibung {f} | registered bond |
| Ordinalzahl {f} Ordnungszahl {f} | ordinal number |
| Ordinate {f} Y-Achse {f} [math.] | Ordinaten {pl} | ordinate axis of ordinates | ordinates |
| Ordinatenachse {f} Y-Achse {f} [math.] | y-axis vertical axis |
| Ordinatenwert {m} [math.] | y-coordinate |
| Ordination {f} | ordination |
| Ordner {m} Mappe {f} | aktiver Ordner | folder | active folder |
| Ordner {m} Ordnerin {f} | steward |
| Ordner {m} | Ordner {pl} | formatter | formatters |
| Ordnung {f} | Ordnung halten | Ordnung schaffen Ruhe schaffen | in Ordnung bringen | nicht in Ordnung sein kaputt sein | order | to keep order | to establish order | to put in order | to be out of order |
| Ordnung {f} | alphabetische Ordnung | numerische Ordnung | systematische Ordnung | order | alphabetical order | numerical order | systematic order |
| Ordnung {f} Anordnung {f} | arrangement |
| Ordnung {f} Regelmäßigkeit {f} | orderliness |
| Ordnung {f} [math.] | order |
| Ordnung machen | Ordnung machend | to neaten | neatening |
| in guter Ordnung | shipshape |
| in bester Ordnung | in apple-pie order |
| in schönster Ordnung | as right as a trivet |
| in schönster Ordnung | as right as a rivet |
| in Ordnung | alright |
| in Ordnung bringen | to fix up [Am.] |
| in Ordnung | hanky-dory |
| Ordnungs... | ordinal |
| Ordnungsprinzip {n} | principle of arrangement |
| Ordnungsprinzip {n} | principle of classification |
| Ordnungssystem {n} | arrangement system |
| Ordnungssystem {n} | classification system |
| Ordnungssystem {n} | system of ordering |
| Ordnungswort {n} | entry word heading word |
| Ordinale {f} | ordinal |
| Ordnungsdaten {pl} (Schlüsseldaten) [comp.] | key data |
