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B1 noun ˈɒk.sɪ.dʒən

oxygen

oxígeno. Un gas incoloro e inodoro, esencial para la vida.
Meaning
A colorless, odorless reactive gas, the chemical element of atomic number 8 and the life-supporting component of the air.
Example
Oxygen is vital for life.
El oxígeno es vital para la vida.
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.
B2 noun /ˈɒs.trɪtʃ/

Ostrich

avestruz
Meaning
a large flightless bird native to Africa with long legs and neck
Example
The ostrich is the world's largest bird.
El avestruz es el pájaro más grande del mundo.
B1 verb /ˈɔːrɡənaɪz/

organize

organizar
Meaning
to arrange systematically; to plan and coordinate
Example
She organized a surprise party for her friend.
Ella organizó una fiesta sorpresa para su amiga.
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.
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.
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.
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.
C1 verb /aʊtˈwɪt/

outwit

superar con astucia
Meaning
to defeat or gain an advantage over someone by being more clever or cunning
Example
The fox managed to outwit the hunters.
El zorro logró engañar a los cazadores.
B2 verb /əˈblaɪdʒ/

oblige

obligar
Meaning
to compel or require someone to do something; to help or do a favor
Example
I would be happy to oblige you with the information you need.
Estaría feliz de obligarte con la información que necesitas.
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 noun ˌɒp.tɪ.maɪˈzeɪ.ʃən

optimization

optimización
Meaning
Improving processes to increase performance and efficiency.
Example
SEO optimization helps websites rank higher on search engines.
La optimización de SEO ayuda a los sitios web a obtener un rango más alto en los motores de búsqueda.
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.
C2 noun /ˈɔːrdnəns/

ordnance

suministros militares
Meaning
Military supplies including weapons, ammunition, and combat equipment.
Example
The army stored ordnance in a secure facility outside the city.
El ejército almacenó suministros militares en una instalación segura fuera de la ciudad.
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.
A1 adjective /ˈɔːr.ɪndʒ/

Orange

naranja
Meaning
having a color between red and yellow like that of a ripe orange fruit
Example
The orange sunset painted the sky magnificently.
El atardecer naranja pintó el cielo magníficamente.
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.
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 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 adjective /əbˈstrʌk.tɪv/

Obstructive

obstructivo
Meaning
deliberately creating difficulties or preventing progress; hindering or blocking something
Example
The obstructive policies hindered economic growth.
Las políticas obstructivas obstaculizaron el crecimiento económico.
B2 verb /ɒpt/

opt

elegir
Meaning
to choose or decide to do something instead of something else
Example
Many students opt to study abroad for better opportunities.
Muchos estudiantes optan por estudiar en el extranjero para tener mejores oportunidades.
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 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 /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.
C2 adjective /ˌoʊvərˈwiːnɪŋ/

overweening

excesivamente arrogante
Meaning
excessively arrogant or prideful
Example
His overweening pride cost him many friends.
Su exceso de orgullo le costó muchos amigos.
C1 noun əˈblɪv.i.ən

oblivion

olvido, destrucción, desaparición
Meaning
The state of being unaware or unconscious of what is happening; complete forgetfulness.
Example
His name faded into oblivion over time.
Su nombre se desvaneció en el olvido con el tiempo.
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.
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.
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.
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.
C1 noun /ˈɔːrkɪd/

Orchid

órquidea
Meaning
a diverse family of flowering plants known for their exotic and often fragrant flowers
Example
The white orchid on the windowsill bloomed for months.
La orquídea blanca en el alféizar de la ventana floreció durante meses.
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.
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.
C2 noun /ˈəʊpəs/

opus

obra creativa
Meaning
A creative work, especially a large and important piece of music or art.
Example
The composer considered the symphony his greatest opus.
El compositor consideró la sinfonía su mayor obra creativa.
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.
C2 verb /ˈɑːblɪˌɡeɪt/

obligate

obligar
Meaning
to bind legally or morally; to compel someone to do something
Example
The contract obligates the company to provide timely service.
El contrato obliga a la empresa a proporcionar un servicio puntual.
C1 adjective /oʊˈvɜːrt/

overt

abierto
Meaning
Done or shown openly; not hidden or secret.
Example
There was an overt display of hostility between the rivals.
Hubo una exhibición abierta de hostilidad entre los rivales.
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.
C1 verb /əˈfɪʃieɪt/

officiate

oficiar
Meaning
To perform official duties, especially in a ceremony or as a referee.
Example
The priest will officiate the wedding ceremony.
El sacerdote oficiará la ceremonia de la boda.
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 noun /ˈɒfʃuːt/

offshoot

ramificación
Meaning
A branch or result that develops from something larger or more important.
Example
The startup was an offshoot of a major tech company.
La startup fue una ramificación de una gran empresa de tecnología.
B2 noun /ˌɔː.ri.enˈteɪ.ʃən/

orientation

orientación
Meaning
the process of becoming familiar with a new situation or environment
Example
The company provides an orientation for all new employees.
La empresa ofrece una orientación para todos los nuevos empleados.
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.
C1 noun /ɒpˈtɒmɪtrɪst/

optometrist

optometrista
Meaning
A healthcare professional who examines eyes and prescribes corrective lenses.
Example
The optometrist prescribed new glasses for her.
El optometrista le recetó nuevos anteojos.
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.
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 /ˈɔːrɡənaɪzər/

organizer

organizador
Meaning
a person who arranges or coordinates activities, events, or groups; a tool or item used to keep things in order
Example
She worked as the main organizer of the international conference.
Ella fue la principal organizadora de la conferencia internacional.
C2 noun /ɒkˈteɪvoʊ/

octavo

octavo (tamaño de libro resultante de doblar una hoja en ocho partes)
Meaning
A size of book page resulting from folding a sheet of paper into eight leaves (sixteen pages).
Example
The old library contained rare octavo editions of Shakespeare.
La antigua biblioteca contenía ediciones raras de octavo de Shakespeare.
B2 noun /əˈpoʊ.nənt/

Opponent

oponente; rival
Meaning
a person who disagrees with or resists a proposal or practice; someone who competes against another
Example
The chess player defeated his strongest opponent.
El jugador de ajedrez derrotó a su oponente más fuerte.
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.
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.
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.
C2 adjective /ˈoʊ.kən/

oaken

hecho de roble
Meaning
made of or resembling oak wood
Example
The villagers gathered around the oaken table in the hall.
Los aldeanos se reunieron alrededor de la mesa de roble en el salón.
C1 adjective /ˌaʊtˈlændɪʃ/

outlandish

extraño
Meaning
Looking or sounding bizarre or unfamiliar; strange.
Example
He wore an outlandish costume to the festival.
Él llevaba un traje extraño al festival.
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.
B1 verb /əbˈzɜːrv/

observe

observar
Meaning
to watch carefully; to notice or perceive something
Example
Scientists observe the behavior of animals in the wild.
Los científicos observan el comportamiento de los animales en la naturaleza.
A1 adverb /aʊt/

out

fuera
Meaning
moving or appearing away from the inside or center; not at home or present
Example
He stepped out of the room quietly.
Él salió de la habitación en silencio.
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.
C2 adjective /əˈrækjələr/

oracular

oracular
Meaning
Resembling an oracle; giving wise, mysterious, or prophetic statements
Example
Her oracular words left the audience deep in thought.
Sus palabras oraculares dejaron a la audiencia profundamente pensativa.
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 verb /əbˈstrʌkt/

obstruct

obstruir
Meaning
to block or hinder progress; to prevent or impede movement
Example
The fallen tree obstructed the road for several hours.
El árbol caído obstruyó el camino durante varias horas.
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 noun /ˈɒbsɪkwi/

obsequy

obsequio
Meaning
A funeral rite, usually used in plural form obsequies.
Example
The village gathered for the obsequy of their beloved teacher.
El pueblo se reunió para el obsequio de su querido maestro.
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 adjective /əbˈsiːkwɪəs/

obsequious

servil
Meaning
Excessively obedient or attentive in a servile way.
Example
The waiter gave an obsequious bow to every customer.
El camarero hizo una reverencia servil a cada cliente.
A2 noun /ˈɔr.dər/

Order

orden; secuencia
Meaning
a command or instruction; the arrangement of things following a particular sequence
Example
The teacher gave an order to sit down quietly.
El maestro dio una orden para sentarse tranquilamente.
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.
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 /ˈɒm.ɪ.nəs/

Ominous

ominoso; amenazante
Meaning
giving the impression that something bad will happen; threatening; foreboding
Example
The dark clouds looked ominous before the storm.
Las nubes oscuras se veían ominosas antes de la tormenta.
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.
B1 noun ˌɔː.ɡən.aɪˈzeɪ.ʃən

organization

organización
Meaning
An organized group of people with a particular purpose, such as a business or government department.
Example
The organization was officially inaugurated in 2024.
La organización fue inaugurada oficialmente en 2024.
C2 verb /ˈɑːbdʒərˌɡeɪt/

objurgate

reprender severamente
Meaning
to scold or rebuke severely
Example
The teacher objurgated the student for being dishonest.
El maestro reprendió severamente al estudiante por ser deshonesto.
C1 noun ˌoʊ.vɚˈɡreɪ.zɪŋ

overgrazing

sobrepastoreo
Meaning
The practice of allowing livestock to graze to the point of damaging vegetation.
Example
Overgrazing leads to soil erosion and loss of biodiversity.
El sobrepastoreo lleva a la erosión del suelo y la pérdida de biodiversidad.
B1 adjective /əˈrɪdʒ.ɪ.nəl/

Original

original; primario; auténtico
Meaning
first; fundamental; primary; authentic
Example
This is the original document, not a copy.
Este es el documento original, no una copia.
C2 noun /ɒmˈnɪpətəns/

omnipotence

omnipotencia
Meaning
The quality of having unlimited power or authority.
Example
Many religions describe God’s omnipotence as absolute.
Muchas religiones describen la omnipotencia de Dios como absoluta.
C2 noun /əˈblɪkwɪti/

obliquity

oblicuidad
Meaning
Deviation from moral or usual conduct; indirectness or lack of straightforwardness.
Example
The politician was criticized for the obliquity of his answers.
El político fue criticado por la oblicuidad de sus respuestas.
C2 adjective /ˌɔːfˈkiː/

off-key

desafinado
Meaning
out of tune; not in accordance with expected standards
Example
The singer was slightly off-key during the performance.
El cantante estaba ligeramente desafinado durante la actuación.
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.
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.
B2 adverb /ˌoʊvərˈnaɪt/

Overnight

de la noche a la mañana; de repente; muy rápidamente
Meaning
during the night; suddenly; very quickly
Example
The city was transformed overnight.
La ciudad fue transformada de la noche a la mañana.
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.
C1 noun /ˈaʊtˌkraɪ/

outcry

protesta
Meaning
A strong expression of public anger or disapproval.
Example
The decision sparked an outcry among the citizens.
La decisión provocó una protesta entre los ciudadanos.
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.
B2 noun /ˈaʊtskɜːrts/

outskirts

afueras de la ciudad
Meaning
The outer parts of a town or city, away from the center.
Example
They moved to the outskirts of the city for a quieter life.
Se mudaron a las afueras de la ciudad para una vida más tranquila.
C2 adjective /ɒmˈnɪʃ.ənt/

Omniscient

omnisciente
Meaning
having complete knowledge; all-knowing
Example
The narrator in the novel appears to be omniscient, knowing every character's thoughts.
El narrador en la novela parece ser omnisciente, conociendo todos los pensamientos de los personajes.
C1 noun /oʊˈeɪ.sɪs/

Oasis

oasis
Meaning
a fertile spot in a desert where water is found; a pleasant refuge
Example
The travelers found an oasis after days in the desert.
Los viajeros encontraron un oasis después de varios días en el desierto.
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 /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.
C2 noun ˌɒbfəsˈkeɪʃən

obfuscation

ofuscación, confusión
Meaning
The action of making something obscure, unclear, or unintelligible.
Example
The obfuscation of the data made it difficult to interpret.
La ofuscación de los datos dificultó su interpretación.
C2 noun /ˈɔːrzmən/

Oarsman

remero
Meaning
a person who rows a boat, especially as a member of a racing crew
Example
The experienced oarsman rowed the boat across the river.
El experimentado remero remó el bote a través del río.
C2 noun /ˈoʊɡər/

ogre

ogro
Meaning
A mythical monster, often depicted as large, hideous, and cruel; metaphorically, a cruel or terrifying person.
Example
The villagers feared the ogre who lived in the dark forest.
Los aldeanos temían al ogro que vivía en el bosque oscuro.
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 noun /ɒpˈtɪʃən/

optician

optometrista
Meaning
A person who makes or sells glasses and contact lenses.
Example
The optician adjusted my new glasses to fit better.
El optometrista ajustó mis nuevas gafas para que quedaran mejor.
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 verb /aʊst/

oust

destituir
Meaning
To remove someone from a position or place of power or authority.
Example
The rebels ousted the dictator from power.
Los rebeldes destituyeron al dictador del poder.
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.
B1 noun ˌɔː.ɡən.aɪˈzeɪ.ʃənz

organizations

organizaciones
Meaning
Organized groups of people with a particular purpose
Example
Organizations play a key role in policymaking.
Las organizaciones desempeñan un papel clave en la toma de decisiones políticas.
B2 adjective /ˈɒp.ʃən.əl/

Optional

opcional
Meaning
not compulsory; left to choice
Example
Wearing a tie is optional for this event.
Usar una corbata es opcional para este evento.
C2 noun ˈɒpjʊləns

opulence

opulencia
Meaning
Great wealth or luxuriousness.
Example
The opulence of the mansion was evident in its ornate furnishings.
La opulencia de la mansión era evidente en sus muebles ornamentados.
C2 noun /ˈɒbsɪkwiːz/

obsequies

ritos fúnebres
Meaning
Funeral rites or ceremonies.
Example
The obsequies for the late leader drew thousands of mourners.
Los ritos fúnebres para el líder fallecido atrajeron a miles de dolientes.
C1 verb /aʊtˈlæst/

outlast

perdurar más tiempo que
Meaning
to continue longer than; to endure beyond someone or something else
Example
The old castle has outlasted many generations.
El viejo castillo ha perdurado más que muchas generaciones.
A2 noun /ˈʌn.jən/

Onion

cebolla
Meaning
a round vegetable with a strong taste and smell, made up of many layers
Example
I need to chop some onions for the curry recipe.
Necesito cortar algunas cebollas para la receta de curry.
B2 adjective /ˈɒnɡəʊɪŋ/

ongoing

en curso
Meaning
continuing; still in progress
Example
The ongoing project will finish next month.
El proyecto en curso terminará el próximo mes.
B1 adjective /ˌoʊld ˈfæʃənd/

old-fashioned

anticuado
Meaning
not modern; belonging to an earlier time
Example
He still wears an old-fashioned hat.
Él todavía usa un sombrero anticuado.
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 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.
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 /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.
A2 adverb /ˈɒbviəsli/

obviously

obviamente
Meaning
in a way that is easily perceived or understood; clearly
Example
Obviously, he didn’t read the instructions.
Obviamente, él no leyó las instrucciones.
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.
C2 noun /ɔːrˈθɑːɡrəfi/

orthography

ortografía
Meaning
The conventional spelling system of a language.
Example
English orthography can be confusing for learners.
La ortografía del inglés puede ser confusa para los estudiantes.
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.
C1 adjective /ˈɔːrdɪnəl/

ordinal

ordinal
Meaning
Relating to the order or position of something in a sequence (first, second, third, etc.).
Example
The ordinal number 'third' indicates position in a sequence.
El número ordinal 'tercero' indica la posición en una secuencia.
A2 verb /ˈɔːfər/

offer

ofrecer
Meaning
to present something for acceptance or rejection; to propose
Example
She offered to help with the project.
Ella se ofreció a ayudar con el proyecto.
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.
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.
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.
C1 noun /ˈɑd.ɪ.ti/

Oddity

rareza
Meaning
something that is strange or unusual; a peculiar trait
Example
His habit of sleeping standing up was considered an oddity.
Su hábito de dormir de pie se consideraba una rareza.
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.
B2 noun oʊˈbiː.sə.t̬i

obesity

obesidad
Meaning
The condition of being grossly fat or overweight.
Example
Obesity increases the risk of diabetes and heart disease.
La obesidad aumenta el riesgo de diabetes y enfermedades cardíacas.
B1 noun əbˈdʒek.tɪv

objective

objetivo
Meaning
A thing aimed at or sought; a goal.
Example
The main objective is to test sustainability.
El objetivo principal es probar la sostenibilidad.