officiate
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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.
B2 noun /ˈɒkjʊpənt/

occupant

ocupante
Meaning
A person who resides in or is present in a house, vehicle, seat, or place.
Example
The car had three occupants at the time of the accident.
El coche tenía tres ocupantes en el momento del accidente.
C1 verb ˈɔːr.kɪ.streɪt

orchestrate

coordinar
Meaning
To plan or coordinate the elements of (a situation) to produce a desired effect, especially surreptitiously.
Example
He skillfully orchestrated the entire event.
Él organizó hábilmente todo el evento.
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.
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.
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.
A2 adjective/adverb /ˈɒnˌlaɪn/

online

en línea
Meaning
connected to or available through the internet
Example
I prefer shopping online rather than going to stores.
Prefiero comprar en línea en lugar de ir a las tiendas.
C2 adjective /ˌoʊpəˈlɛsənt/

opalescent

opalescente
Meaning
showing or reflecting a milky, iridescent light like an opal
Example
The opalescent sky glowed with shades of pink and blue.
El cielo opalescente brillaba con tonos de rosa y azul.
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.
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.
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.
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.
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/verb /ˈoʊvərˌdoʊs/

overdose

sobredosis
Meaning
An excessive and dangerous amount of a drug; to take too much of a substance.
Example
He was rushed to the hospital after a drug overdose.
Fue llevado al hospital después de una sobredosis de drogas.
B1 noun /ˈɑb.stə.kəl/

Obstacle

obstáculo
Meaning
something that blocks or makes progress difficult; a barrier
Example
Bad weather was the main obstacle to our journey.
El mal tiempo fue el principal obstáculo para nuestro viaje.
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.
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.
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 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.
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.
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.
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.
B1 noun /ˌɒpəˈreɪʃən/

operation

operación
Meaning
an act or process of functioning or operating
Example
The hospital performed a successful operation.
El hospital realizó una operación exitosa.
B1 noun /əˈkeɪ.ʒən/

Occasion

ocasión; evento especial
Meaning
a particular time or instance of an event; a special celebration
Example
Their wedding was a joyous occasion.
Su boda fue una ocasión alegre.
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 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.
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 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.
B2 adverb /ˈəʊvəli/

overly

excesivamente
Meaning
to an excessive degree or extent
Example
She was overly concerned about the results.
Ella estaba excesivamente preocupada por los resultados.
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 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 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 noun /ˌoʊvərprəˈdʌkʃən/

overproduction

sobreproducción
Meaning
The act of producing more of something than is needed or can be consumed.
Example
The economic crisis was caused by the overproduction of goods.
La crisis económica fue causada por la sobreproducción de bienes.
C1 noun /əbˈdʒɛktər/

objector

opositor
Meaning
a person who expresses opposition or disapproval to something
Example
The objector raised his concerns during the town meeting.
El opositor expresó sus preocupaciones durante la reunión del consejo.
B1 noun /əˈpɪn.jən/

Opinion

opinión
Meaning
a view or judgment formed about something; a belief or assessment based on grounds short of proof
Example
In my opinion, this is the best solution.
En mi opinión, esta es la mejor solución.
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.
A1 conjunction /ɔːr/

or

o
Meaning
used to link alternatives
Example
You can have tea or coffee.
Puedes tomar té o café.
C2 noun /əbˈstrʌkʃənɪst/

obstructionist

obstruccionista
Meaning
a person who deliberately delays or prevents progress by being uncooperative or oppositional
Example
The obstructionist in the committee kept delaying the decision-making process.
El obstruccionista en el comité siguió retrasando el proceso de toma de decisiones.
C2 verb /əbˈvɜːrt/

obvert

invertir
Meaning
To turn something so as to face in a different direction; in logic, to convert a proposition by negating both subject and predicate.
Example
The teacher asked the students to obvert the statement for practice.
El maestro pidió a los estudiantes que obvirtieran la declaración para practicar.
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.
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.
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 /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.
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 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.
C1 noun /ˈɑːdəsi/

odyssey

viaje largo
Meaning
a long, adventurous journey; a series of experiences
Example
Her career has been an odyssey of challenges and achievements.
Su carrera ha sido una odisea de desafíos y logros.
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 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.
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.
C1 adjective /ˈɒptɪməm/

optimum

óptimo
Meaning
Most conducive to a favorable outcome; best.
Example
To achieve optimum results, we need to improve efficiency.
Para lograr los mejores resultados, necesitamos mejorar la eficiencia.
C1 adjective /əbˈsɛsɪv/

obsessive

obsesivo
Meaning
Relating to or characterized by an obsession; thinking about something too much.
Example
He has an obsessive interest in cleanliness.
Él tiene un interés obsesivo en la limpieza.
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.
C2 adjective /əˈfɪʃəs/

officious

entrometido
Meaning
Excessively eager to offer unwanted help or advice; meddlesome.
Example
The officious guard kept interrupting the visitors with unnecessary instructions.
El guardia entrometido interrumpía a los visitantes con instrucciones innecesarias.
C1 adjective /ɒˈstɛnsəbl/

ostensible

aparente
Meaning
stated or appearing to be true, but not necessarily so
Example
His ostensible reason for leaving was illness, but many doubted it.
Su aparente razón para irse era la enfermedad, pero muchos lo dudaron.
C1 noun /ˈəʊ.nəs/

onus

responsabilidad
Meaning
A duty or responsibility, especially a heavy one.
Example
The onus is on the government to provide relief to the victims.
El ónus está en el gobierno para proporcionar alivio a las víctimas.
B2 verb /ˌoʊvərˈloʊd/

overload

sobrecargar
Meaning
to load with too much weight or cargo; to give too much work or information
Example
Don't overload the washing machine or it might break down.
No sobrecargues la lavadora o podría romperse.
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.
C1 adjective /ˈɒptɪk/

optic

óptico
Meaning
Relating to the eye or vision.
Example
The optic nerve carries signals from the eye to the brain.
El nervio óptico lleva señales desde el ojo al cerebro.
B2 noun /ˈɔr.fən.ɪʒ/

Orphanage

orfanato
Meaning
an institution for the care and education of children who have lost their parents
Example
The charity built a new orphanage for homeless children.
La caridad construyó un nuevo orfanato para niños sin hogar.
A1 adjective /oʊˈkeɪ/

ok

está bien
Meaning
used to indicate agreement, approval, or understanding
Example
Okay, let's go to the park.
Está bien, vamos al parque.
C1 noun ˈoʊʃən əˌsɪdɪfɪˈkeɪʃən

ocean acidification

acidificación oceánica
Meaning
The ongoing decrease in the pH of the Earth's oceans, caused by the absorption of carbon dioxide from the atmosphere.
Example
Ocean acidification is caused by atmospheric CO2 absorption.
La acidificación oceánica es causada por la absorción de CO2 atmosférico.
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.
A1 noun/adjective/adverb /ˌaʊtˈsaɪd/

outside

afuera
Meaning
the external part or surface of something; beyond the boundary
Example
Children were playing outside in the yard.
Los niños estaban jugando afuera en el jardín.
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 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 adjective /ˌfæʃ.ənd/

Outdated

desactualizado
Meaning
obsolete; no longer current
Example
This computer software is completely outdated.
Este software de computadora está completamente desactualizado.
A1 adverb /ˈɔːfən/

often

a menudo
Meaning
frequently, many times
Example
I often visit my grandparents on weekends.
A menudo visito a mis abuelos los fines de semana.
C1 adjective /əbˈtjuːs/

Obtuse

tonto; obtuso; lento de comprensión
Meaning
annoyingly insensitive or slow to understand; lacking in intelligence or perception
Example
He was being deliberately obtuse about the instructions.
Él estaba siendo deliberadamente obtuso sobre las instrucciones.
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.
C2 noun /oʊf/

Oaf

una persona torpe, estúpida o insensible
Meaning
a clumsy, stupid, or insensitive person
Example
Don't be such an oaf - handle the dishes carefully!
¡No seas un oaf así - maneja los platos con cuidado!
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.
C2 noun /ˌɒktədʒəˈnɛəriən/

octogenarian

octogenario
Meaning
A person who is between 80 and 89 years old.
Example
The octogenarian still jogs every morning to stay healthy.
El octogenario aún corre todas las mañanas para mantenerse saludable.
A1 preposition /ʌv/

of

de
Meaning
expressing the relationship between a part and a whole
Example
The book is on the table, in front of the window.
El libro está sobre la mesa, frente a la ventana.
C2 verb ˈɑːb.fə.skeɪt

obfuscate

ofuscar, oscurecer, confundir
Meaning
Render obscure, unclear, or unintelligible.
Example
Politicians often obfuscate facts to mislead people.
Los políticos a menudo ofuscan los hechos para engañar a la gente.
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.
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.
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.
C1 noun /əˈfen.dər/

Offender

delincuente; infractor de la ley
Meaning
a person who commits an illegal act; someone who breaks the law
Example
The young offender was sentenced to community service.
El joven delincuente fue sentenciado a servicio comunitario.
C2 noun /ˈɒksɪdənt/

occident

occidente
Meaning
The countries of the West, especially Europe and America.
Example
The Occident has a long history of philosophical thought.
El occidente tiene una larga historia de pensamiento filosófico.
C2 adjective /ˈoʊ.vɔɪd/

ovoid

ovoide
Meaning
egg-shaped; resembling an oval or ellipse
Example
The artist painted an ovoid shape in the center of the canvas.
El artista pintó una forma ovoide en el centro del lienzo.
B1 noun /ˈɔːfɪsər/

officer

oficial
Meaning
a person in a position of authority, especially in law enforcement
Example
The officer gave him a ticket for speeding.
El oficial le dio una multa por exceso de velocidad.
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.
B2 noun /ˈaʊtɪŋ/

outing

excursión
Meaning
a short trip or excursion, often for leisure or enjoyment
Example
They had a lovely outing at the beach last weekend.
Tuvieron una maravillosa excursión en la playa el fin de semana pasado.
C2 verb /ˈɑːskjʊleɪt/

osculate

besar
Meaning
To kiss.
Example
They osculated under the mistletoe during the party.
Ellos se besaron debajo del muérdago durante la fiesta.
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.
B2 verb /ˈɒkjʊpaɪ/

occupy

ocupar
Meaning
to take up space or time; to live or work in a place
Example
The new family will occupy the house next month.
La nueva familia ocupará la casa el próximo mes.
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.
C2 noun /ˈoʊ.kəm/

oakum

fibra de cuerda vieja
Meaning
loose fibers obtained by untwisting old ropes, used for caulking ships
Example
The shipbuilders used oakum to seal the gaps in the wooden planks.
Los constructores de barcos usaron oakum para sellar las grietas en las tablas de madera.
B2 noun /ɑːks/

Ox

buey
Meaning
a large strong animal used for pulling heavy loads or plowing fields
Example
The farmer used an ox to plow the field.
El agricultor usó un buey para arar el campo.
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.
A1 verb, adjective /oʊn/

own

poseer
Meaning
to possess something; belonging to oneself
Example
She owns a beautiful house in the city.
Ella posee una hermosa casa en la ciudad.
B2 noun /ˈaʊtlet/

outlet

salida
Meaning
a means by which something is released, expressed, or distributed
Example
Art is a great outlet for emotions.
El arte es una gran salida para las emociones.
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.
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 /ˈoʊ.vər.let/

Overlet

colchón adicional
Meaning
a thin mattress or pad placed over a bed for additional comfort
Example
The overlet makes the bed more comfortable to sleep on.
El overlet hace la cama más cómoda para dormir.
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.
B2 verb /ˌoʊvərˈpeɪ/

overpay

pagar en exceso
Meaning
To pay more than is necessary or reasonable.
Example
She realized she had overpaid for the concert tickets.
Ella se dio cuenta de que había pagado de más por las entradas del concierto.
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 /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.
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 ˈɒksɪdʒən prəˈdʌkʃən

oxygen production

producción de oxígeno
Meaning
The process of generating oxygen through photosynthesis or other means.
Example
Plants are vital for oxygen production and the maintenance of life.
Las plantas son vitales para la producción de oxígeno y el mantenimiento de la vida.
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 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.
A1 interjection /oʊ/

oh

¡Oh!
Meaning
used to express surprise, realization, or understanding
Example
Oh, I didn't know you were here!
¡Oh, no sabía que estabas aquí!
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.
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.
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.
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.
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 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.
C1 noun /ɒpˈtɒmətri/

optometry

optometría
Meaning
The practice or profession of examining the eyes and prescribing corrective lenses.
Example
She studied optometry at the university to become an eye specialist.
Estudió optometría en la universidad para convertirse en especialista en ojos.
C1 adjective /ˈaʊt.kɑːst/

Outcast

rechazado
Meaning
rejected by society; excluded person
Example
He felt like an outcast in his new school.
Él se sintió como un rechazado en su nueva escuela.
C1 noun /ɔːr/

Oar

remo
Meaning
a long pole with a flat blade used to row a boat
Example
He dipped the oar into the water and pulled the boat forward.
Sumergió el remo en el agua y empujó el bote hacia adelante.
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.
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.
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 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.
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.
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 /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.