overarching
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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 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 /ˈɒfərtɔːri/

offertory

ofrenda
Meaning
The part of a religious service when offerings are collected; the offering itself.
Example
The offertory was taken during the Sunday service.
La ofrenda fue tomada durante el servicio del domingo.
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.
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.
B2 noun /ˈoʊ.vər ɡroʊθ/

Over growth

crecimiento excesivo
Meaning
excessive growth beyond normal size; too much development or expansion
Example
The overgrowth of weeds made the garden look untidy.
El crecimiento excesivo de las malas hierbas hizo que el jardín pareciera descuidado.
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.
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.
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.
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 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.
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.
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.
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.
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.
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.
C2 verb /ˌoʊvərˈliːp/

overleap

saltar por encima
Meaning
To jump over something; to omit or disregard something.
Example
He managed to overleap the fence easily.
Él logró saltar la cerca fácilmente.
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 /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.
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.
C1 adjective /ˌəʊvərˈstɪmjʊˌleɪtɪd/

overstimulated

sobrestimulado
Meaning
Excessively excited or aroused, overwhelmed by too much stimulus.
Example
Overstimulated minds can lead to burnout and decreased productivity.
Las mentes sobrestimuladas pueden conducir al agotamiento y a una menor productividad.
C1 noun /ˈoʊvərˌsiːər/

overseer

supervisor
Meaning
a person who supervises work or workers; a manager
Example
The overseer made sure the workers followed safety rules.
El supervisor se aseguró de que los trabajadores siguieran las reglas de seguridad.
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.
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.
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.
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.
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.
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.
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.
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.
C1 noun ˌɒk.sɪˈdeɪ.ʃən

oxidation

oxidación
Meaning
A chemical reaction that involves the combination of a substance with oxygen, often causing deterioration.
Example
Oxidation causes metal surfaces to weaken.
La oxidación debilita las superficies metálicas.
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.
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.
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.
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.
C1 adjective /ˌɒmnɪˈprezənt/

omnipresent

omnipresente
Meaning
(of God) present everywhere at the same time.
Example
Social media has become an omnipresent force in modern society.
Las redes sociales se han convertido en una fuerza omnipresente en la sociedad moderna.
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 noun /ˈɒrɪz(ə)n/

orison

oración
Meaning
a prayer, especially a devout or formal one
Example
He whispered a quiet orison before going to sleep.
Susurró una oración tranquila antes de dormir.
B2 verb /ˌoʊvərˈlʊk/

overlook

pasar por alto
Meaning
to fail to notice or consider something; to have a view from above
Example
It's easy to overlook small details when you're in a hurry.
Es fácil pasar por alto los pequeños detalles cuando tienes prisa.
C2 noun /ˈɒb.stɪ.nə.si/

obstinacy

obstinación
Meaning
Stubborn refusal to change one's opinion or chosen course of action, despite attempts to persuade one to do so.
Example
His obstinacy made negotiations difficult.
Su obstinación hizo que las negociaciones fueran difíciles.
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 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.
C2 adjective /ɔːrˈθɑːɡənl/

orthogonal

ortogonal
Meaning
at right angles; independent or unrelated
Example
In mathematics, two vectors are orthogonal if their dot product is zero.
En matemáticas, dos vectores son ortogonales si su producto punto es cero.
B1 adjective /əˈfɪʃəl/

official

oficial
Meaning
relating to or connected with an authority or public office
Example
He is the official spokesperson for the company.
Él es el portavoz oficial de la empresa.
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.
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.
B2 adjective; verb (past participle) /ˈɒkjʊpaɪd/

occupied

ocupado
Meaning
being in use or taken; filled or lived in; controlled or held by force
Example
The room is occupied, so please wait outside.
La habitación está ocupada, por favor espere afuera.
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.
B2 noun/verb /ˌoʊvərˈlæp/

overlap

solapamiento
Meaning
To extend over and cover partly; an area where things coincide.
Example
The two meetings overlap by an hour.
Las dos reuniones se solapan por una hora.
C2 noun /ˌɒpəˈrɛtə/

operetta

ópera ligera
Meaning
a short opera with light and humorous themes
Example
The theater staged a famous operetta by Gilbert and Sullivan.
El teatro presentó una famosa opereta de Gilbert y Sullivan.
B2 noun /əˈfɛns/

offense

delito
Meaning
an illegal act; a crime
Example
The offense was committed in broad daylight.
El delito fue cometido a plena luz del día.
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.
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.
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.
B1 adjective /əˈbiː.di.ənt/

Obedient

obediente
Meaning
willing to comply with orders or instructions; submissive
Example
The obedient student always follows the teacher's instructions.
El estudiante obediente siempre sigue las instrucciones del profesor.
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.
B2 noun /ˈaʊtˌfɪt/

outfit

conjunto de ropa
Meaning
A set of clothes worn together, often for a particular occasion.
Example
She wore a beautiful outfit to the party.
Ella usó un hermoso conjunto de ropa para la fiesta.
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.
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.
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.
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.
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 noun /ˌaʊtˈsaɪdə(r)/

outsider

extranjero
Meaning
a person who is not accepted as a member of a particular group or community
Example
As a new student, she often felt like an outsider at school.
Como estudiante nuevo, a menudo se sentía como una extranjera en la escuela.
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.
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 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.
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.
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.
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.
B2 verb /ˌoʊvərˈkʌm/

overcome

superar
Meaning
To succeed in dealing with a problem or difficulty.
Example
You can overcome procrastination with planning.
Puedes superar la procrastinación con planificación.
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.
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.
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 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.
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.
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.
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 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 adjective /əˈlɪmpɪk/

olympic

olímpico
Meaning
related to the Olympic Games, a major international sporting event
Example
She trained hard to compete in the Olympic Games.
Ella entrenó duro para competir en los Juegos Olímpicos.
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.
B2 noun /ˈaʊt.breɪk/

Out-break

brote
Meaning
a sudden occurrence or eruption of something, especially disease or violence
Example
The outbreak of flu affected many students in the school.
El brote de gripe afectó a muchos estudiantes en la escuela.
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.
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.
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.
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/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.
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.
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 /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.
C2 adjective /ɒmˈnɪp.ə.tənt/

omnipotent

omnipotente
Meaning
Having unlimited power; able to do anything; all-powerful.
Example
In many religions, God is considered omnipotent.
En muchas religiones, Dios se considera omnipotente.
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.
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.
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 adjective /ˈɒsiəs/

osseous

óseo
Meaning
consisting of or turned into bone; bony
Example
The fossil showed osseous structures of the ancient creature.
El fósil mostró estructuras óseas de la antigua criatura.
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.
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 /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 adjective /ˌɑːpərˈtuːn/

opportune

momento oportuno
Meaning
Happening at a suitable or convenient time.
Example
She arrived at an opportune moment to help.
Llegó en un momento oportuno para ayudar.
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.
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.
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.
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 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.
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 noun (plural) /ˈɔːrdʒiːz/

orgies

orgías
Meaning
Wild gatherings involving excessive indulgence in food, drink, or sexual activity.
Example
The ancient Romans were infamous for their lavish feasts and orgies.
Los antiguos romanos eran infames por sus banquetes lujosos y orgías.
C2 noun /ˈɔːrɪndʒfɪn ˈleɪbiːoʊ/

Orangefin labeo

labeo de aleta naranja
Meaning
a freshwater fish species native to South Asian rivers, commonly found in Bangladesh and India
Example
The orangefin labeo is an important food fish in Bangladesh.
El labeo de aleta naranja es un pez alimenticio importante en Bangladesh.
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 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 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.
C2 noun /əbˈstɛtrɪks/

obstetrics

obstetricia
Meaning
The branch of medicine dealing with childbirth and care of women giving birth.
Example
She is studying obstetrics to become a specialist in childbirth.
Ella está estudiando obstetricia para convertirse en especialista en partos.
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.
A2 noun /ˈoʊpənɪŋ/

opening

apertura
Meaning
an act or instance of beginning something
Example
The opening of the new store was a huge success.
La apertura de la nueva tienda fue un gran éxito.
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.
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 /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.
B2 adverb /ˈoʊpənli/

Openly

abiertamente; públicamente
Meaning
in a frank and honest way; without concealment; publicly
Example
She spoke openly about her struggles with mental health.
Ella habló abiertamente sobre sus luchas con la salud mental.
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.
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!
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.
C1 adjective /əbˈdʒek.ʃən.ə.bəl/

Objectionable

objecionable
Meaning
arousing distaste or opposition; unpleasant or offensive
Example
His objectionable behavior made everyone uncomfortable.
Su comportamiento objetable hizo que todos se sintieran incómodos.
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.