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C1 noun /ˌɒk.sɪ.dʒɪˈneɪ.ʃən/

oxygenation

suministro o tratamiento con oxígeno
Meaning
The process of supplying or treating with oxygen.
Example
Deep breathing exercises improve oxygenation of the body.
Los ejercicios de respiración profunda mejoran el suministro de oxígeno en el cuerpo.
B2 noun /ˈɒp.tɪ.mɪ.zəm/

optimism

optimismo
Meaning
Hopefulness and confidence about the future or the successful outcome of something.
Example
Her optimism helped her overcome difficult times.
Su optimismo le ayudó a superar tiempos difíciles.
B2 noun /əˈfens/

Offence

delito; infracción; agravio
Meaning
a breach of law or rule; an annoyance or resentment
Example
Stealing is a serious offence punishable by law.
El robo es un delito grave castigado por la ley.
B2 noun, verb /ˈaʊtlɔː/

outlaw

forajido, ilegalizar
Meaning
as a noun: a person who breaks the law and lives outside its protection; as a verb: to make something illegal
Example
The government decided to outlaw the harmful practice.
El gobierno decidió ilegalizar la práctica perjudicial.
A2 noun əˈlɪm.pɪk ɡeɪmz

Olympic Games

juegos olímpicos
Meaning
The world's largest international sports competition held every four years, bringing together athletes from different countries to compete in various sports.
Example
The Olympic Games bring together the world's top athletes.
Los Juegos Olímpicos reúnen a los mejores atletas del mundo.
C1 adjective /ˌoʊvərˈbɛrɪŋ/

overbearing

opresivo
Meaning
unpleasantly or arrogantly domineering
Example
His overbearing attitude made everyone uncomfortable.
Su actitud opresiva hizo que todos se sintieran incómodos.
C2 noun /ˈɑb.lə.kwi/

Obloquy

crítica severa o abuso verbal; condena pública
Meaning
harsh criticism or verbal abuse; strong public condemnation
Example
The politician faced obloquy after the scandal.
El político enfrentó obloquio después del escándalo.
B2 adjective /aʊtˈreɪdʒəs/

outrageous

atroz
Meaning
Shockingly bad or excessive; very unusual or amusing.
Example
The comedian told an outrageous joke.
El comediante contó un chiste atroz.
C1 noun /ˈoʊvərˌtʊr/

overture

overture / propuesta
Meaning
An introduction to something more substantial; a proposal or preliminary action.
Example
The peace overture was welcomed by both nations.
La propuesta de paz fue bienvenida por ambas naciones.
C2 adjective /ˌɒbsəˈlɛsnt/

obsolescent

obsoleto
Meaning
Becoming outdated or on the way to becoming obsolete.
Example
The obsolescent technology could not compete with modern devices.
La tecnología obsoleta no pudo competir con los dispositivos modernos.
B2 noun /ˈaʊtˌbreɪk/

outbreak

brote
Meaning
a sudden start or occurrence of something unpleasant, like disease or violence
Example
There was an outbreak of flu in the city.
Hubo un brote de gripe en la ciudad.
B2 verb /ˌoʊvərˈduː/

overdo

exagerar
Meaning
to do something too much; to exaggerate or carry to excess
Example
Don't overdo the exercise on your first day at the gym.
No exageres con el ejercicio en tu primer día en el gimnasio.
B2 noun /ˈaʊtˌskɜːrt/

outskirt

las afueras de la ciudad
Meaning
the outer edge or border of a town or city
Example
They built a new factory on the outskirts of the city.
Construyeron una nueva fábrica en las afueras de la ciudad.
B2 adjective /ˌoʊvərˈwɛlmɪŋ/

overwhelming

abrumador
Meaning
Very intense; overpowering.
Example
Large tasks can feel overwhelming.
Las grandes tareas pueden sentirse abrumadoras.
C1 verb ˈɔː.kɪ.streɪ.tɪd

orchestrated

orquestado
Meaning
Planned or coordinated carefully and deliberately.
Example
The attacks were orchestrated with precision.
Los ataques fueron orquestados con precisión.
A2 adjective /ˈaʊtdɔːr/

outdoor

al aire libre
Meaning
situated, existing, or done outside a building
Example
We planned an outdoor picnic for the weekend.
Planeamos un picnic al aire libre para el fin de semana.
C1 verb /ˈɔːstrəˌsaɪz/

ostracize

ostracizar
Meaning
to exclude someone from a group or society; to banish or shun
Example
After the scandal, he was ostracized by his former colleagues.
Después del escándalo, fue ostracizado por sus antiguos compañeros de trabajo.
C2 adjective /ˈɒf.biːt/

offbeat

inusual
Meaning
Unusual, unconventional, or different from the norm.
Example
She has a very offbeat sense of humor.
Ella tiene un sentido del humor muy inusual.
C2 verb /oʊˈpaɪn/

opine

expresar una opinión
Meaning
to express an opinion or belief
Example
The professor opined that the policy would fail.
El profesor opinó que la política fracasaría.
C1 noun /ˈɔr.ə.kəl/

Oracle

oráculo
Meaning
a person regarded as a source of wise counsel; in ancient times, a priest or priestess acting as a medium
Example
The ancient Greeks consulted the oracle at Delphi.
Los antiguos griegos consultaban el oráculo en Delfos.
B2 noun /ˈaʊt.kʌm/

Outcome

resultado; consecuencia;
Meaning
the result or consequence of an action or situation; the final product
Example
The outcome of the election surprised everyone.
El resultado de las elecciones sorprendió a todos.
C1 noun /əˈpreʃ.ən/

Oppression

opresión; abuso; tiranía;
Meaning
cruel or unjust treatment or exercise of authority; the state of being subject to harsh treatment
Example
The people fought against political oppression.
La gente luchó contra la opresión política.
C1 verb /ˌoʊvərˈθroʊ/

overthrow

felicidad
Meaning
To remove a leader or government from power, often by force.
Example
The rebels planned to overthrow the corrupt regime.
No pudo esconder su felicidad cuando recibió el premio.
B1 verb অকার্স

occurs

sucede
Meaning
Happens or takes place, especially as a result of something.
Example
Snowfall occurs in regions with freezing temperatures.
La nieve ocurre en regiones con temperaturas bajo cero.
C2 noun /ˌɒn.əˌmæt.əˈpiː.ə/

onomatopoeia

onomatopeya
Meaning
The formation of a word from a sound associated with what is named.
Example
The word 'buzz' is an example of onomatopoeia.
La palabra 'zumbido' es un ejemplo de onomatopeya.
C2 noun /ˈɔɪl.mən/

Oilman

petrolero
Meaning
a person who works in the oil industry; someone who sells oil or petroleum products
Example
The oilman discovered a new oil field in the desert.
El petrolero descubrió un nuevo campo petrolero en el desierto.
B2 noun /wʌn θɜːd/

one-third

un tercio
Meaning
one part of something that is divided into three equal parts
Example
One-third of the class was absent today.
Un tercio de la clase estaba ausente hoy.
B1 adjective, adverb /ˈoʊvərɔːl/

overall

en general
Meaning
in general or as a whole
Example
Overall, the project has been successful.
En general, el proyecto ha sido exitoso.
B1 noun /ˈɑː.lɪv/

Olive

aceituna
Meaning
a small oval fruit with a hard pit, typically green or black, used for eating or making oil
Example
Olive oil is considered one of the healthiest cooking oils available.
El aceite de oliva se considera uno de los aceites de cocina más saludables disponibles.
B2 noun /ˈaʊtlʊk/

outlook

perspectiva, pronóstico
Meaning
a person's general attitude or view; a forecast or prospect
Example
The economic outlook for the year is positive.
El pronóstico económico para el año es positivo.
B1 noun ˌɒpəˈtjuːnɪtiz

opportunities

oportunidades
Meaning
A set of circumstances that makes it possible to do something; chances for advancement or success.
Example
Opportunities for jobs decreased.
Las oportunidades para trabajos disminuyeron.
C2 noun /ˈaʊtˌrɪɡər/

outrigger

estructura de refuerzo
Meaning
a projecting structure on a boat, used for stability, or a boat fitted with such support
Example
The fisherman paddled his outrigger canoe across the lagoon.
El pescador remó su canoa con outtrigger a través de la laguna.
C1 noun ˌɒb.səˈlɛs.əns

obsolescence

obsolescencia
Meaning
The process of becoming obsolete or outdated and no longer used.
Example
The rapid advancement of technology leads to the obsolescence of old devices.
El rápido avance de la tecnología provoca la obsolescencia de los dispositivos antiguos.
C1 noun /əbˈstrʌkʃən/

obstruction

obstáculo
Meaning
Something that blocks or gets in the way; the action of obstructing.
Example
There was an obstruction on the railway track.
Había un obstáculo en la vía del tren.
B2 noun /ɔːˈræŋ.ʊˌtæŋ/

Orang-Outang

orangután
Meaning
a large arboreal ape with long reddish hair, long arms, and hooked hands and feet, native to Borneo and Sumatra
Example
The orangutan swings gracefully through the forest canopy.
El orangután se balancea graciosamente a través del dosel del bosque.
A2 modal verb /ɔːt/

ought

debería
Meaning
Used to indicate duty, correctness, or moral obligation.
Example
You ought to respect your elders.
Deberías respetar a tus mayores.
B2 noun /ˈoʊvərpæs/

overpass

paso elevado
Meaning
A bridge that carries one road or railway over another.
Example
The new overpass reduced traffic congestion in the city.
El nuevo paso elevado redujo la congestión de tráfico en la ciudad.
C1 noun/verb /ˈoʊvərˌhæŋ/

overhang

saliente
Meaning
To extend outward and hang over something; a projecting part.
Example
The roof overhang provides shade in the summer.
El alero proporciona sombra en el verano.
C1 noun /əbˈzɜːvəns/

observance

observancia
Meaning
The practice of following a custom, rule, or religious law.
Example
The festival is held in observance of a centuries-old tradition.
El festival se celebra en observancia de una tradición centenaria.
C1 adverb /ˈaʊtwədli/

Outwardly

externamente; superficialmente;
Meaning
on the surface; externally; in appearance
Example
Outwardly, he seemed calm, but inside he was nervous.
Exteriormente, parecía tranquilo, pero por dentro estaba nervioso.
C1 verb /uːz/

ooze

filtrarse
Meaning
to slowly flow or leak out through small openings or pores
Example
Blood began to ooze from the small cut.
La sangre comenzó a filtrarse de la pequeña herida.
C1 noun /ˈɔːr.ə.tɔːr.i/

oratory

oratoria
Meaning
The art of public speaking; skilled and confident delivery of speeches to an audience.
Example
His exceptional oratory skills won him the debate competition.
Sus excepcionales habilidades oratorias le ganaron la competencia de debate.
B2 noun /əˌrɪʒ.əˈnæl.ə.ti/

Originality

originalidad
Meaning
the quality of being novel or unusual; the ability to think independently and creatively
Example
The artist's work showed great originality and creativity.
La obra del artista mostró gran originalidad y creatividad.
C2 noun /ˈoʊpiət/

opiate

opiáceo
Meaning
a drug containing opium or its derivatives, used to relieve pain or cause sleep
Example
The doctor prescribed an opiate to relieve the patient's pain.
El médico recetó un opiáceo para aliviar el dolor del paciente.
B1 verb /oʊ/

owe

deber
Meaning
to be under obligation to pay or repay; to be indebted
Example
I owe my success to my parents' support.
Le debo mi éxito al apoyo de mis padres.
C2 noun /ˌɔːrnɪˈθɑːlədʒi/

ornithology

ornitología
Meaning
the scientific study of birds
Example
She pursued ornithology to understand the migration patterns of birds.
Ella persiguió la ornitología para entender los patrones de migración de los pájaros.
B2 adjective /əˈfen.sɪv/

Offensive

ofensivo; insultante; agresivo
Meaning
causing displeasure or resentment; insulting; aggressive
Example
His offensive remarks hurt everyone's feelings.
Sus comentarios ofensivos lastimaron los sentimientos de todos.
C2 verb /ˈoʊɡəl/

ogle

mirar lascivamente
Meaning
To look at someone with obvious sexual interest.
Example
He kept ogling the models on the runway.
Él no podía dejar de mirar las modelos en la pasarela.
C1 adjective /aʊtˈmoʊdɪd/

outmoded

desfasado
Meaning
No longer in fashion or useful; outdated.
Example
That old computer is completely outmoded.
Esa computadora antigua está completamente desfasada.
C2 noun /oʊd/

ode

oda
Meaning
a lyrical poem, often expressing praise or strong emotions
Example
The poet wrote an ode to the beauty of nature.
El poeta escribió una oda a la belleza de la naturaleza.
B2 verb əbˈzɜːrvd

observed

celebrar
Meaning
To celebrate or keep a religious or other festival.
Example
The day is observed annually to raise awareness.
El día se celebra anualmente para aumentar la conciencia.
B2 noun /ˌɒpəˈzɪʃən/

opposition

oposición
Meaning
the action of opposing or resisting something
Example
The opposition to the new law was strong.
La oposición a la nueva ley fue fuerte.
A1 pronoun /ˈʌðərz/

others

otros
Meaning
people or things distinct from the ones already mentioned or known
Example
I like to spend time with others.
Me gusta pasar tiempo con otros.
C2 noun /əbˈsɪdiən/

obsidian

obsidiana (roca volcánica oscura y vidriosa)
Meaning
A hard, dark, glasslike volcanic rock formed by rapid solidification of lava.
Example
The knife was made from sharp obsidian.
El cuchillo estaba hecho de obsidiana afilada.
C2 noun /ˈoʊvərlɔːrd/

overlord

señor
Meaning
A ruler, master, or person of great power and authority over others.
Example
The peasants were forced to pay taxes to their overlord.
Los campesinos fueron obligados a pagar impuestos a su señor.
C1 verb /ˌoʊvərˈruːl/

overrule

anular
Meaning
to reject or disallow by exercising one's superior authority; to override a decision
Example
The judge overruled the objection from the defense attorney.
El juez anuló la objeción del abogado defensor.
C2 noun /ɑːlˈfækʃən/

olfaction

olfato
Meaning
The sense of smell; the process of detecting and perceiving odors.
Example
Dogs have a highly developed sense of olfaction.
Los perros tienen un sentido del olfato muy desarrollado.
B2 noun /əbˈdʒek.ʃən/

Objection

objeción; desacuerdo; protesta;
Meaning
an expression of disagreement or disapproval; a reason for disagreeing
Example
The lawyer raised an objection during the trial.
El abogado levantó una objeción durante el juicio.
B2 noun /ˌoʊ.vɚˈkraʊ.dɪŋ/

overcrowding

hacinamiento excesivo
Meaning
Excessive crowd or packed condition, having more people or vehicles in a place than the approved capacity.
Example
The subway system suffers from severe overcrowding during peak hours.
El sistema de metro sufre de severo hacinamiento durante las horas pico.
C2 adjective /ɒˈstɛnsɪv/

ostensive

ostensible
Meaning
clearly demonstrative or pointing out; explicitly shown
Example
The teacher gave an ostensive example to clarify the concept.
La maestra dio un ejemplo ostensible para aclarar el concepto.
C2 verb /əˈkluːd/

occlude

ocluir
Meaning
To block or close up an opening or passage.
Example
The pipe was occluded by mineral deposits.
La tubería estaba ocluida por depósitos minerales.
B2 adjective /ˈɔː.rəl/

Oral

oral; relacionado con la boca
Meaning
spoken rather than written; relating to the mouth
Example
The oral examination will test your speaking skills.
El examen oral evaluará tus habilidades de hablar.
C2 noun /ˈɔː.rɪ.fɪs/

orifice

orificio
Meaning
an opening or hole, especially in the body or a device
Example
The medicine was applied through a small orifice in the device.
El medicamento se aplicó a través de un pequeño orificio en el dispositivo.
C2 adjective /ˈɒfɪʃ/

offish

distante
Meaning
Unfriendly, distant, or reserved in manner.
Example
He seemed offish at the party and avoided most conversations.
Parecía distante en la fiesta y evitaba la mayoría de las conversaciones.
B2 verb /ˌoʊvərˈwɛlm/

overwhelm

abrumar
Meaning
to overpower someone emotionally or physically; to be too much to handle
Example
She was overwhelmed with gratitude after receiving the help.
Ella estaba abrumada de gratitud después de recibir la ayuda.
A2 verb /oʊˈbeɪ/

obey

obedecer
Meaning
to follow orders or instructions; to comply with rules
Example
Children should obey their parents and teachers.
Los niños deben obedecer a sus padres y maestros.
C1 noun ɔːrˈdiːl

ordeal

prueba difícil
Meaning
A physical or mental painful experience that must be endured
Example
Surviving the wilderness was a tough ordeal for them.
Sobrevivir en la naturaleza fue una dura prueba para ellos.
B1 noun /ˈɔr.ə.ʒɪn/

Origin

origen
Meaning
the point or place where something begins, arises, or is derived; the source
Example
Scientists are studying the origin of the universe.
Los científicos están estudiando el origen del universo.
A1 preposition /ɒn/

on

sobre
Meaning
physically in contact with and supported by a surface
Example
The book is on the table.
El libro está sobre la mesa.
B1 verb /ˈɒpəreɪtɪŋ/

operating

operando
Meaning
to control or manage the functioning of something
Example
The company has been operating in this market for five years.
La compañía ha estado operando en este mercado durante cinco años.
A2 noun /ˈoʊ.ʃən/

ocean

océano
Meaning
A very large expanse of sea, especially the main areas of sea between continents.
Example
The ocean covers more than 70% of the Earth's surface.
El océano cubre más del 70% de la superficie de la Tierra.
C1 verb /ˈɒp.tɪ.maɪz/

optimize

optimizar
Meaning
To make the best or most effective use of a situation, opportunity, or resource.
Example
The company is working to optimize its supply chain.
La empresa está trabajando para optimizar su cadena de suministro.
C1 noun /ˈɒstrəsɪzəm/

ostracism

ostracismo
Meaning
The act of excluding someone from a group or society.
Example
The student faced ostracism after breaking the rules.
El estudiante enfrentó el ostracismo después de romper las reglas.
C2 adjective /ˈoʊ.pən ˈhɑrt.ɪd/

Open-hearted

de corazón abierto; generoso y sincero; cálidamente receptivo;
Meaning
Kind and generous; sincere and honest; warmly receptive;
Example
She welcomed the strangers with an open-hearted smile and invited them for dinner.
Ella dio la bienvenida a los extraños con una sonrisa de corazón abierto e invitó a cenar.
C1 noun /ˌɑːk.sɪˈmɔːr.ɒn/

oxymoron

oxímoron
Meaning
a figure of speech where two contradictory terms are combined
Example
The phrase 'deafening silence' is a classic oxymoron.
La frase 'silencio ensordecedor' es un oxímoron clásico.
C2 noun /ˈɒkjʊlɪst/

oculist

optometrista
Meaning
An old-fashioned term for an eye doctor or ophthalmologist.
Example
The village oculist was known for treating various eye diseases.
El oculista del pueblo era conocido por tratar diversas enfermedades oculares.
A1 verb /ˈoʊpən/

open

abrir
Meaning
to move something so as to allow access; to begin
Example
Please open the door for me.
por favor abre la puerta para mí.
B2 noun /ˈaʊt.saɪ.dər/

Out-sider

extranjero
Meaning
a person who does not belong to a particular group; someone not accepted by a group
Example
As an outsider, he found it difficult to understand their traditions.
Como extranjero, le resultó difícil entender sus tradiciones.
C1 adjective /oʊˈbiːs/

obese

obeso
Meaning
Extremely overweight; having an excessive amount of body fat.
Example
The doctor advised the obese patient to adopt a healthier lifestyle.
El doctor le recomendó al paciente obeso adoptar un estilo de vida más saludable.
C1 adjective/adverb /ˌɒfˈhænd/

offhand

sin pensar
Meaning
Without previous thought or preparation; casual and sometimes dismissive.
Example
She gave an offhand reply to his serious question.
Ella dio una respuesta sin pensarlo a su seria pregunta.
C1 adjective ˈɒk.sɪ.də.tɪv

oxidative

Relacionado con la oxidación
Meaning
Related to or caused by oxidation, especially cellular damage from free radicals.
Example
Excess stress can lead to oxidative damage in cells.
El estrés excesivo puede causar daño oxidativo en las células.
A1 noun /ɒkˈtoʊbər/

october

octubre
Meaning
the tenth month of the year in the Gregorian calendar
Example
The weather becomes cooler in October.
El clima se vuelve más fresco en octubre.
C1 adjective ˈɒptɪmaɪzd

optimized

optimizados, mejorado, más eficiente
Meaning
Made as fully perfect, functional, or effective as possible; improved to achieve maximum efficiency.
Example
The system has been optimized for faster performance.
El sistema ha sido optimizado para un rendimiento más rápido.
B2 verb /ˌoʊvərˈteɪk/

overtake

adelantar
Meaning
to catch up with and pass someone or something; to surpass
Example
The runner managed to overtake his competitor in the final lap.
El corredor logró adelantar a su competidor en la última vuelta.
C2 adjective /ˌoʊdəˈrɪfərəs/

odoriferous

fragante
Meaning
having or giving off a smell, especially a strong or pleasant one
Example
The garden was filled with odoriferous flowers.
El jardín estaba lleno de flores fragantes.
B2 noun ˈaʊt.pʊt

output

producción
Meaning
The amount of something produced by a person, machine, or industry.
Example
Climate change reduces agricultural output.
El cambio climático reduce la producción agrícola.
C1 verb əˈblɪt.ə.reɪt

obliterate

destruir
Meaning
To destroy utterly; wipe out completely, to erase or remove something completely.
Example
The storm obliterated entire villages.
La tormenta destruyó aldeas enteras.
B1 adjective /ˌoʊvərˈweɪt/

overweight

sobrepeso
Meaning
heavier than is considered healthy or normal
Example
The doctor advised him to lose weight as he was overweight.
El doctor le aconsejó perder peso ya que tenía sobrepeso.
B2 noun /ˌɑb.lɪˈɡeɪ.ʃən/

Obligation

obligación
Meaning
a duty or commitment; something that must be done legally or morally
Example
Parents have an obligation to care for their children.
Los padres tienen la obligación de cuidar a sus hijos.
B2 verb /ˌoʊvərˈtɜrn/

overturn

dar la vuelta / revertir una decisión
Meaning
to turn something upside down or to reverse a decision or judgment
Example
The court decided to overturn the previous ruling.
El tribunal decidió anular la decisión anterior.
B2 noun /ˈɒfərɪŋ/

offering

oferta
Meaning
something that is given, especially as a gift or contribution
Example
The company’s latest offering is an eco-friendly car.
La última oferta de la empresa es un coche ecológico.
C1 verb /ˌaʊtˈweɪ/

outweigh

ser más importante
Meaning
To be more important, valuable, or significant than something else.
Example
The benefits of the new policy outweigh the risks.
Los beneficios de la nueva política superan los riesgos.
B2 verb /əˈrɪdʒɪneɪt/

originate

originar
Meaning
to come into existence; to begin; to create or produce
Example
The tradition originated in ancient times.
La tradición se originó en tiempos antiguos.
C1 adjective /əˈprɛs.ɪv/

Oppressive

opresivo
Meaning
Harsh and authoritarian; overwhelming; causing distress; tyrannical;
Example
The oppressive heat made it difficult to work outside during the summer.
El calor opresivo dificultaba trabajar afuera durante el verano.
A1 adjective /ˈʌðər/

other

otro
Meaning
used to refer to something different from the one already mentioned or known
Example
I don't want this one, I will take the other one.
No quiero este, tomaré el otro.
C2 noun /ˌɔːrnɪˈθɒlədʒɪst/

ornithologist

ornitólogo
Meaning
a scientist who studies birds
Example
The ornithologist spent years studying migratory birds.
El ornitólogo pasó años estudiando aves migratorias.
B2 noun /ˈaʊt.laɪn/

Outline

esquema; contorno; resumen
Meaning
a general description or plan showing the essential features of something; the main points
Example
The teacher provided an outline of the course syllabus.
El maestro proporcionó un esquema del syllabus del curso.
B2 noun /ˈɔːrnəmənt/

ornament

adorno
Meaning
A decorative object that adds beauty to something.
Example
The Christmas tree was decorated with colorful ornaments.
El árbol de Navidad estaba decorado con adornos de colores.
A2 noun /ɔɪl/

Oil

aceite
Meaning
a viscous liquid derived from petroleum or plants, used for cooking or fuel
Example
Heat the oil in a pan before adding the vegetables.
Calienta el aceite en una sartén antes de añadir las verduras.
C1 noun /ˈɒn.slɔːt/

onslaught

asalto
Meaning
A fierce or destructive attack.
Example
The village faced an onslaught of enemy forces.
El pueblo enfrentó un asalto de las fuerzas enemigas.
C1 adjective /ˌəʊ.vərˈɑː.tʃɪŋ/

overarching

global, abarcante, integral
Meaning
Comprehensive or all-embracing; forming an arch over something.
Example
The overarching theme of the book is human resilience.
El tema global del libro es la resistencia humana.
B2 adjective /ˈɒp.tɪ.məl/

optimal

óptimo, más favorable
Meaning
Best or most favorable; the most effective under particular conditions.
Example
The optimal temperature for plant growth is around 25°C.
La temperatura óptima para el crecimiento de las plantas es de alrededor de 25°C.
A2 noun /ˈɒf.ɪs/

office

oficina
Meaning
a room or building where people work, usually at desks
Example
She left the office early to attend a family event.
Ella dejó la oficina temprano para asistir a un evento familiar.
C1 noun /ˈoʊ.mən/

Omen

presagio de buena o mala suerte futura
Meaning
an event regarded as a sign of future good or bad luck
Example
Many people consider a black cat crossing your path a bad omen.
Muchas personas consideran que un gato negro cruzando tu camino es un mal presagio.
C1 noun /ˈɑːlɪˌɡɑːrki/

oligarchy

oligarquía
Meaning
A small group of people having control of a country, organization, or institution.
Example
The nation was ruled by a wealthy oligarchy that controlled all resources.
La nación fue gobernada por una oligarquía rica que controlaba todos los recursos.
B2 noun ˈəʊnəʃɪp

ownership

propiedad
Meaning
The act, state, or right of possessing something; legal title to something.
Example
Ownership of resources was crucial.
La propiedad de los recursos fue crucial.
C2 verb /ˈɑːbvieɪt/

obviate

eliminar
Meaning
To remove a need or difficulty; to prevent or avoid something.
Example
This new system obviates the need for manual data entry.
Este nuevo sistema elimina la necesidad de ingresar datos manualmente.
C1 noun /ˈɒktɪv/

octave

octava
Meaning
A series of eight musical notes, or the interval between one musical pitch and another with double its frequency.
Example
The singer's voice could easily reach the higher octave.
La voz del cantante podría alcanzar fácilmente la octava más alta.
B1 adjective /ˈaʊtər/

outer

exterior
Meaning
situated on or toward the outside; external
Example
The outer layer of the jacket is waterproof.
La capa externa de la chaqueta es impermeable.
A2 noun /ˈoʊ.nər/

Owner

dueño
Meaning
a person who owns something; someone who has legal possession of property
Example
The owner of the restaurant greeted us warmly.
El dueño del restaurante nos saludó calurosamente.
C2 noun /oʊˈbeɪsəns/

obeisance

reverencia
Meaning
A gesture of respect such as a bow or curtsy.
Example
They bowed in obeisance to the king.
Ellos se inclinaron en reverencia al rey.
C1 adjective /əˈblɪɡ.ə.tɔː.ri/

obligatory

obligatorio
Meaning
Required by a legal, moral, or other rule; compulsory.
Example
Wearing a seatbelt is obligatory in most countries.
Usar el cinturón de seguridad es obligatorio en la mayoría de los países.
C2 adjective /ˈɑːbdjʊrət/

obdurate

obstinado
Meaning
Stubbornly refusing to change one's opinion or course of action.
Example
He remained obdurate despite everyone's pleas.
Él permaneció obstinado a pesar de las súplicas de todos.
B2 adjective /aʊtˈstændɪŋ/

outstanding

extraordinario
Meaning
extremely good or impressive; not yet resolved or paid
Example
She received an award for her outstanding performance.
Recibió un premio por su actuación extraordinaria.
C1 adjective /ˌɒstɛnˈteɪʃəs/

ostentatious

ostentoso
Meaning
Characterized by a showy or pretentious display intended to impress others.
Example
He wore an ostentatious gold chain to the party.
Llevaba una cadena de oro ostentosa en la fiesta.
A2 noun /ˈɒbdʒɪkt/

object

objeto
Meaning
a thing that can be seen and touched
Example
The table is an object in the room.
La mesa es un objeto en la habitación.
C1 adjective əˈblɪv.i.əs

oblivious

despreocupado
Meaning
Being completely unaware of surrounding events.
Example
He was oblivious to the noise around him while reading.
Él no se dio cuenta del ruido a su alrededor mientras leía.
A2 adverb; noun /ˌaʊtˈdɔːrz/

outdoors

al aire libre
Meaning
outside a building; the natural environment outside
Example
We spent the whole afternoon outdoors enjoying the fresh air.
Pasamos toda la tarde al aire libre disfrutando del aire fresco.
C1 noun /ˌɑːsɪˈleɪʃən/

oscillation

oscilación
Meaning
The movement back and forth at a regular speed.
Example
The oscillation of the pendulum controls the clock.
La oscilación del péndulo controla el reloj.
C2 noun /ˌɔːrəˈtɔːri.oʊ/

oratorio

composición musical religiosa
Meaning
A large-scale musical composition for orchestra, choir, and soloists, usually on a sacred theme, performed without costumes or scenery.
Example
Handel's 'Messiah' is one of the most famous oratorios ever written.
El 'Mesías' de Handel es uno de los oratorios más famosos jamás escritos.
C1 adjective /əbˈnɒkʃəs/

Obnoxious

odioso
Meaning
extremely unpleasant; offensive; annoying
Example
His obnoxious behavior at the party annoyed everyone.
Su comportamiento odioso en la fiesta molestó a todos.