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B1 adverb /əˈrɪdʒɪnəli/

originally

originalmente
Meaning
in the beginning, at first
Example
Originally, she wanted to be a doctor.
Originalmente, ella quería ser doctora.
C2 adjective /ˈɔːrnəri/

ornery

gruñón
Meaning
bad-tempered and combative; stubborn
Example
The ornery old man refused to leave his chair.
El gruñón anciano se negó a dejar su silla.
C1 adjective /ˈɒptɪkəl/

optical

óptico
Meaning
related to or used in seeing or sight
Example
The optical illusion fooled everyone at the exhibition.
La ilusión óptica engañó a todos en la exposición.
C2 noun /ˌoʊpəˈlɛsəns/

opalescence

opalescencia
Meaning
a milky or pearly appearance of a surface like that of an opal
Example
The pearl had a gentle opalescence under the light.
La perla tenía una suave opalescencia bajo la luz.
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.
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 noun /ˈɒptɪks/

optics

óptica
Meaning
The branch of physics dealing with light and vision.
Example
She studied optics to understand how lenses work.
Ella estudió óptica para entender cómo funcionan las lentes.
C2 adjective /ˈɑːsɪˌfaɪd/

ossified

convertido en hueso, rígido
Meaning
Turned into bone or become rigid; unwilling to change.
Example
The company had an ossified management structure that resisted innovation.
La empresa tenía una estructura de gestión rígida que resistía la innovación.
C2 adjective /ˈəʊ.dər.əs/

Odorous

fragante; aromático
Meaning
having a strong smell; fragrant; aromatic
Example
The garden was filled with odorous flowers.
El jardín estaba lleno de flores fragantes.
C2 noun /əˈprəʊ.bri.əm/

opprobrium

desprecio, oprobio
Meaning
Harsh criticism or public disgrace.
Example
The scandal brought opprobrium on the politician.
El escándalo trajo desprecio al político.
A1 adjective /oʊld/

old

viejo
Meaning
having lived for a long time; not new or young
Example
He still drives his old car.
Él todavía conduce su coche viejo.
B2 noun /əbˈzɜːvər/

observer

observador
Meaning
a person who watches or notices something
Example
The observer took notes during the meeting.
El observador tomó notas durante la reunión.
A2 noun /ˈɒm.lət/

Omelet

tortilla
Meaning
a dish made from beaten eggs cooked in a frying pan and often folded around a filling
Example
She made a cheese omelet for breakfast.
Ella hizo una tortilla de queso para el desayuno.
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.
C2 noun /ˌɑːpərˈtuːnɪzəm/

opportunism

oportunismo
Meaning
The practice of taking advantage of opportunities regardless of principles or ethics.
Example
His decision was driven by opportunism, not values.
Su decisión fue impulsada por el oportunismo, no por los valores.
C1 noun /ˈɔːrdɪnəns/

ordinance

ordenanza
Meaning
An authoritative rule, law, or decree issued by a city, town, or authority.
Example
The city council passed an ordinance banning smoking in public parks.
El consejo municipal aprobó una ordenanza que prohíbe fumar en los parques públicos.
A1 pronoun, noun, adjective /wʌn/

one

uno
Meaning
the number equivalent to the sum of zero and one; a single person or thing
Example
Only one student answered the question.
Solo un estudiante respondió la pregunta.
C1 verb /ˌoʊvərˈʃædoʊ/

overshadow

opacar
Meaning
to appear more important or significant than something else, reducing its impact
Example
The scandal overshadowed his achievements.
El escándalo opacó sus logros.
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 verb /ˌoʊvərˈstraɪd/

overstride

cruzar dando pasos largos
Meaning
To stride over something; to step across with long steps.
Example
He managed to overstride the narrow stream with ease.
Él logró cruzar el estrecho arroyo con facilidad.
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.
B1 noun /aʊl/

Owl

búho
Meaning
a nocturnal bird of prey with large eyes and a hooked beak
Example
The owl hooted softly in the darkness of the forest.
El búho hooteó suavemente en la oscuridad del bosque.
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.
B2 verb /əbˈteɪn/

obtain

obtener
Meaning
to get or acquire something
Example
You need to obtain a visa before traveling abroad.
Necesitas obtener una visa antes de viajar al extranjero.
C1 noun /oʊθ/

Oath

juramento
Meaning
a solemn promise or declaration; a sworn statement
Example
The doctor took an oath to help patients.
El doctor hizo un juramento de ayudar a los pacientes.
C1 noun /ˈaʊtpoʊst/

outpost

puesto avanzado
Meaning
A small military camp or position at some distance from the main force, used especially as a guard.
Example
The soldiers were stationed at a remote outpost.
Los soldados fueron apostados en un puesto avanzado remoto.
B2 noun /ˈɔːɡənɪzəm/

organism

organismo
Meaning
a living thing that has an organized structure and can grow and reproduce
Example
Every organism needs water to survive.
Todo organismo necesita agua para sobrevivir.
C1 adjective /ˈəʊnərəs/

onerous

arduo
Meaning
involving a great deal of effort, difficulty, or burden
Example
Fulfilling the contract proved to be an onerous task for the company.
Cumplir el contrato resultó ser una tarea ardua para la empresa.
C2 adjective /ˈɒkjʊlər/

ocular

ocular
Meaning
Relating to the eye or vision.
Example
The patient was referred to a specialist for ocular treatment.
El paciente fue referido a un especialista para tratamiento ocular.
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.
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.
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.
C1 noun /ˈaʊtˌɡroʊθ/

outgrowth

desarrollo
Meaning
something that grows out of something else; a natural development or result
Example
The new policy was an outgrowth of years of debate.
La nueva política fue un desarrollo de años de debate.
C1 noun /ˌɒbstəˈtrɪʃən/

obstetrician

obstetra
Meaning
A doctor specializing in pregnancy, childbirth, and women's reproductive health.
Example
The obstetrician monitored the mother’s health throughout the pregnancy.
El obstetra monitoreó la salud de la madre durante el embarazo.
B2 noun ˈoʊzoʊn dɪˈpliʃən

ozone depletion

depleción de ozono
Meaning
The reduction in the amount of ozone in the Earth's stratosphere, leading to increased UV radiation.
Example
Ozone depletion increases UV radiation.
La depleción de ozono aumenta la radiación UV.
C1 noun /oʊˈbɪt.ʃu.er.i/

Obituary

obituario
Meaning
a notice of someone's death published in a newspaper; biographical account of deceased person
Example
The newspaper published his obituary yesterday.
El periódico publicó su obituario ayer.
B2 noun /ˈɒpəreɪtər/

operator

operador
Meaning
a person who operates equipment, a business, or controls something
Example
The machine operator ensured that everything ran smoothly.
El operador de la máquina se aseguró de que todo funcionara sin problemas.
C2 verb /əbˈtruːd/

obtrude

obstruir
Meaning
to force oneself or one's ideas into a situation uninvited or inappropriately
Example
He didn’t want to obtrude into their private conversation.
Él no quería obstruir su conversación privada.
B2 adjective /ˌɔːɡənaɪˈzeɪʃənəl/

organizational

organizacional
Meaning
relating to the structure or arrangement of a company or group
Example
He works on improving the organizational structure of the company.
Él trabaja en mejorar la estructura organizacional de la empresa.
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.
A2 preposition /ˈɒntu/

onto

sobre
Meaning
moving to a position on the surface of something
Example
She jumped onto the table to get the book.
Ella saltó sobre la mesa para coger el libro.
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.
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.
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.
C2 noun /ˈɔːrdʒi/

orgy

fiesta desmedida
Meaning
A wild party involving excessive indulgence, especially of a sexual nature.
Example
The novel described a scandalous orgy in a wealthy mansion.
La novela describió una orgía escandalosa en una mansión rica.
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.
B2 noun /ˈɔr.fən/

Orphan

huérfano
Meaning
a child whose parents are dead; someone without protective support
Example
The orphan was adopted by a loving family.
El huérfano fue adoptado por una familia amorosa.
B1 adverb /əˈkeɪʒənəli/

Occasionally

ocasionalmente; de vez en cuando;
Meaning
sometimes; from time to time; not regularly
Example
I occasionally visit my grandmother on weekends.
A veces visito a mi abuela los fines de semana.
C1 noun /əbˈzɜːrvətɔːri/

observatory

observatorio
Meaning
A building equipped for observing astronomical or meteorological events.
Example
The observatory is open to the public on weekends.
El observatorio está abierto al público los fines de semana.
C1 noun /ˈɑn.set/

Onset

inicio; comienzo
Meaning
the beginning or early stages of something; the start of a medical condition
Example
The onset of winter brought heavy snowfall.
El inicio del invierno trajo fuertes nevadas.
C2 noun /ˈɒlɪv bɑːb/

Olive barb

barbo oliva
Meaning
A small freshwater fish with olive-colored body and barbels
Example
The olive barb is commonly found in South Asian rivers.
El barbo oliva se encuentra comúnmente en los ríos del sur de Asia.
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 /oʊliˈændər/

Oleander

oleandro
Meaning
a poisonous evergreen shrub with clusters of white, pink, or red flowers
Example
The beautiful oleander flowers bloomed in the garden despite their toxic nature.
Las hermosas flores de oleandro florecieron en el jardín a pesar de su naturaleza tóxica.
B2 verb /oʊˈmɪt/

omit

omitir
Meaning
to leave out or exclude; to fail to include something
Example
Please don't omit any important details from your report.
Por favor, no omitas detalles importantes de tu informe.
B2 adjective /əˈpəʊzd/

opposed

opuesto
Meaning
being against or in disagreement with something
Example
She is strongly opposed to animal testing.
Ella está firmemente en contra de las pruebas con animales.
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.
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.
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 noun /ˈaʊtˌsɛt/

outset

comienzo
Meaning
the beginning or start of something
Example
From the outset, the project seemed ambitious but achievable.
Desde el comienzo, el proyecto parecía ambicioso pero alcanzable.
C1 verb /ɔːrˈdeɪn/

ordain

ordenar
Meaning
To officially make someone a priest or minister; to decree or order something officially.
Example
The bishop will ordain three new priests this Sunday.
El obispo ordenará tres nuevos sacerdotes este domingo.
B2 adjective /ˈɔː.də.li/

Orderly

ordenado; sistemático; pacífico
Meaning
well-organized; systematic; peaceful
Example
Please keep your desk orderly and clean.
Por favor, mantén tu escritorio ordenado y limpio.
C1 noun /ˈɒktəɡən/

octagon

octágono
Meaning
A polygon with eight sides and eight angles.
Example
The stop sign is shaped like an octagon.
La señal de alto tiene forma de octágono.
C1 adjective /ˌaʊt ən ˈaʊt/

out-and-out

completo
Meaning
complete; absolute; used to emphasize something extreme
Example
The speech was an out-and-out lie.
El discurso fue una mentira completa.
B2 adjective + noun ˈɒptɪməl ˈtempərətʃər

optimal temperature

temperatura óptima
Meaning
The best or most favorable temperature for a particular purpose
Example
Winter provides optimal temperature for farming.
El invierno proporciona la temperatura óptima para la agricultura.
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.
C1 adjective /ɔːˈneɪt/

ornate

ornamentado
Meaning
elaborately or highly decorated
Example
The palace hall was filled with ornate furniture and paintings.
El salón del palacio estaba lleno de muebles ornamentados y pinturas.
C2 verb /ˈɔːreɪt/

orate

orar
Meaning
To speak in a formal, often pompous manner
Example
He began to orate at the ceremony.
Él comenzó a orar en la ceremonia.
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 /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.
B2 adjective /ˈɔɪl.i/

Oily

oleoso; cubierto de aceite; grasoso
Meaning
covered with oil; containing oil; greasy
Example
Her oily skin needs special care.
Su piel aceitosa necesita cuidados especiales.
C2 noun /ˈɔːfəl/

offal

vísceras
Meaning
the internal organs and entrails of an animal used as food; waste parts
Example
The butcher prepared sausages using pork offal.
El carnicero preparó salchichas usando vísceras de cerdo.
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.
B1 adverb /ˈʌðərwaɪz/

Otherwise

de otra manera; si no; o sino
Meaning
in a different way; if not; or else; apart from that
Example
Study hard, otherwise you will fail the exam.
Estudia mucho, de lo contrario, reprobarás el examen.
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.
C1 adjective /ˈɑp.ər.ə.tɪv/

Operative

activo; en efecto; funcionando; operativo;
Meaning
Functioning; in effect; working; active;
Example
The new safety protocols became operative immediately after the accident.
Los nuevos protocolos de seguridad se volvieron operativos inmediatamente después del accidente.
C1 verb /ˌaʊtˈstrɪp/

outstrip

superar
Meaning
To go faster or do better than someone or something; to surpass.
Example
The company outstripped its competitors in sales last year.
La compañía superó a sus competidores en ventas el año pasado.
C2 adjective /əbˈtruːsɪv/

obtrusive

obtrusivo
Meaning
noticeable in an unpleasant or unwelcome way; intrusive
Example
The advertisement was so obtrusive that it ruined the user’s experience.
El anuncio era tan obtrusivo que arruinó la experiencia del usuario.
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.
B1 noun /ˈɒbstəkəlz/

obstacles

obstáculos
Meaning
Things that block one's way or prevent or hinder progress.
Example
Obstacles in life can often lead to valuable lessons.
Los obstáculos en la vida a menudo conducen a lecciones valiosas.
C1 adjective /ˌɔː.riˈen.təl/

Oriental

relativo a los países del Este de Asia; oriental
Meaning
relating to the countries of East Asia; eastern
Example
The museum has a beautiful collection of oriental art.
El museo tiene una hermosa colección de arte oriental.
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 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.
C2 adjective /əˈprəʊ.bri.əs/

opprobrious

despectivo
Meaning
Expressing strong criticism or scorn.
Example
He made opprobrious remarks about his opponent.
Él hizo comentarios despectivos sobre su oponente.
C1 verb /ˌoʊvərˈpaʊər/

overpower

dominar
Meaning
To defeat or gain control over someone or something by using greater strength or force.
Example
The soldiers managed to overpower the enemy forces.
Los soldados lograron dominar las fuerzas enemigas.
B2 verb /ˌoʊvərˈsiː/

oversee

supervisar
Meaning
to supervise or watch over something; to manage and direct
Example
The manager will oversee the entire construction project.
El gerente supervisará todo el proyecto de construcción.
B2 noun /ˈɔːɡən/

organ

órgano
Meaning
a part of the body that performs a specific function
Example
The heart is an important organ in the human body.
El corazón es un órgano importante en el cuerpo humano.
C2 verb /ˌaʊtməˈnuːvər/

outmaneuver

superar astutamente
Meaning
to gain an advantage over an opponent by skillful or clever action
Example
The smaller company managed to outmaneuver its larger rival.
La empresa más pequeña logró superar astutamente a su rival más grande.
C2 adjective /ˈoʊ.pən ˈhæn.dɪd/

Open-handed

generoso; liberal
Meaning
Generous; liberal; giving freely;
Example
He is very open-handed with his money and always helps those in need.
Él es muy generoso con su dinero y siempre ayuda a los necesitados.
B2 adverb /ˈɒdli/

oddly

extrañamente
Meaning
in a strange or unusual way; unexpectedly
Example
Oddly, he didn’t seem upset by the bad news.
Extrañamente, no parecía molesto por la mala noticia.
A2 adjective /ˈɑp.ə.zɪt/

Opposite

opuesto; completamente diferente; cara a cara; inverso;
Meaning
Contrary; completely different; facing each other; reverse;
Example
They have opposite views on politics but remain good friends.
Tienen puntos de vista opuestos sobre la política, pero siguen siendo buenos amigos.
A1 conjunction /ɔːr/

or

o
Meaning
used to link alternatives
Example
You can have tea or coffee.
Puedes tomar té o café.
B2 noun ɔːˈɡæn.ɪk fuːdz

organic foods

alimentos orgánicos
Meaning
Food produced without the use of chemicals such as artificial pesticides, fertilizers, or other artificial agents.
Example
Organic foods are healthier than processed foods.
Los alimentos orgánicos son más saludables que los alimentos procesados.
A1 adverb /ɔːf/

off

apagado
Meaning
away from a place, position, or time; not functioning
Example
He turned off the light before leaving the room.
Apagó la luz antes de salir de la habitación.
B2 noun /ˈɔːkɪstrə/

orchestra

orquesta
Meaning
a large group of musicians playing different instruments together
Example
The orchestra performed beautifully at the concert.
La orquesta actuó maravillosamente en el concierto.
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.
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.
B1 adjective /əˈkeɪ.ʒən.əl/

Occasional

ocasional
Meaning
occurring infrequently or irregularly; happening from time to time
Example
She enjoys occasional walks in the park.
Ella disfruta de paseos ocasionales en el parque.
C1 adjective /ˌɔːrnəˈmɛntl/

ornamental

ornamental
Meaning
Serving as decoration; decorative rather than functional.
Example
The garden was filled with ornamental plants.
El jardín estaba lleno de plantas ornamentales.
B2 noun /oʊˈbiː.di.əns/

Obedience

obediencia
Meaning
compliance with an order, request, or law; submission to authority
Example
Children should show obedience to their parents.
Los niños deben mostrar obediencia a sus padres.
C1 adjective əʊˈpeɪk

opaque

opaco, impenetrable, difícil de entender
Meaning
Not able to be seen through; not transparent; difficult to understand.
Example
The glass was too opaque to see through.
El vidrio era tan opaco que no se podía ver a través de él.
A1 adjective /əʊˈkeɪ/

okay

está bien
Meaning
used to express agreement or acceptance
Example
It's okay to leave early today.
Está bien irse temprano hoy.
C2 noun ˈoʊʃən ˌstrætɪfɪˈkeɪʃən

ocean stratification

estratificación oceánica
Meaning
The formation of layers in ocean water due to differences in density.
Example
Ocean stratification affects marine biodiversity.
La estratificación oceánica afecta la biodiversidad marina.
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 verb /ˈɒs.ɪ.leɪt/

oscillate

moverse o balancearse de un lado a otro entre dos puntos o estados
Meaning
To swing or move back and forth between two points or states
Example
The stock market tends to oscillate during uncertain times.
El mercado de valores tiende a oscilar durante tiempos inciertos.
C2 adjective /ˈoʊdiəs/

odious

odioso
Meaning
extremely unpleasant or repulsive
Example
The dictator was remembered for his odious crimes.
El dictador fue recordado por sus odiosos crímenes.
B2 adjective ˌɒp.ərˈeɪ.ʃən.əl

operational

operativo
Meaning
In working order; ready for use.
Example
The space project will be operational by 2025.
El proyecto espacial estará operativo para 2025.
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.
B2 noun /ˈɔɪ.stər/

Oyster

ostra
Meaning
a type of shellfish that can be eaten and sometimes contains pearls
Example
She ordered fresh oysters at the seafood restaurant.
Ella ordenó ostras frescas en el restaurante de mariscos.
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.
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.
C2 noun /ˌɒstɛnˈteɪʃən/

ostentation

ostentación
Meaning
excessive display of wealth or knowledge intended to attract admiration or envy
Example
The billionaire’s party was full of ostentation and luxury.
La fiesta del multimillonario estaba llena de ostentación y lujo.
B2 noun/verb /ˈaʊtreɪdʒ/

outrage

indignación
Meaning
A strong feeling of anger and shock; to arouse anger or shock.
Example
The unfair decision caused public outrage.
La decisión injusta causó una indignación pública.
C2 verb /aʊtˈraɪd/

outride

adelantar
Meaning
to ride faster, farther, or better than someone else
Example
The young rider managed to outride his competitors in the race.
El joven jinete logró adelantar a sus competidores en la carrera.
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.
B1 verb /əˈkɜːr/

occur

ocurrir
Meaning
to happen or take place; to be found or present
Example
The accident occurred at the intersection during rush hour.
El accidente ocurrió en la intersección durante la hora punta.
C1 noun /ˈaʊtriːtʃ/

outreach

expansión de la asistencia
Meaning
The act of providing services or support to people who might not otherwise have access to them.
Example
The charity launched a new outreach program for the homeless.
La caridad lanzó un nuevo programa de expansión de la asistencia para las personas sin hogar.
C1 verb /ˌaʊtˈduː/

outdo

superar
Meaning
To do better than someone else; to surpass.
Example
She always tries to outdo her classmates in exams.
Ella siempre trata de superar a sus compañeros de clase en los exámenes.
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.
C1 noun /əˈkɜr.əns/

Occurrence

suceso
Meaning
an instance or event of something happening; the fact of occurring
Example
The occurrence of earthquakes is common in this region.
La ocurrencia de terremotos es común en esta región.
C1 adjective /ˌɒbsəˈliːt/

obsolete

obsoleto
Meaning
No longer in use or out of date.
Example
Floppy disks are now completely obsolete.
Los disquetes ahora están completamente obsoletos.
C1 adjective /ɒmˈnɪv.ər.əs/

Omnivorous

omnívoro
Meaning
eating both plants and animals; feeding on various kinds of food
Example
Bears are omnivorous animals that eat both plants and meat.
Los osos son animales omnívoros que comen tanto plantas como carne.