Oxford 3000 Words Starting with O – Complete List with Meanings & Quizzes

obey verb

Short meaning: to follow rules or do what you are told.

Example: Children should obey their parents.

object noun / verb

Short meaning: a thing you can see or touch; also to disagree with something.

Example: Many people objected to the plan.

objective noun / adjective

Short meaning: a goal; also describes something based on facts, not feelings.

Example: The main objective is to improve skills.

observation noun

Short meaning: the act of watching something carefully.

Example: The doctor kept the patient under observation.

observe verb

Short meaning: to watch something carefully.

Example: Scientists observe how animals behave.

obtain verb

Short meaning: to get something, especially through effort.

Example: You need a permit to obtain this document.

obvious adjective

Short meaning: clear and easy to understand.

Example: It’s obvious that he is tired.

obviously adverb

Short meaning: in a way that is clear to see or understand.

Example: Obviously, the results are positive.

occasion noun

Short meaning: a particular event or time when something happens.

Example: They met on a special occasion.

occasionally adverb

Short meaning: sometimes but not often.

Example: We go out occasionally.

occupied adjective

Short meaning: busy doing something; also describes a place being used.

Example: The seat is occupied.

occupy verb

Short meaning: to take up space or time; to live in or use a place.

Example: They occupy the top floor.

occur verb

Short meaning: to happen.

Example: The accident occurred at night.

ocean noun

Short meaning: a very large body of salt water.

Example: The Pacific Ocean is huge.

o'clock adverb

Short meaning: used to show the exact hour of the day.

Example: The class starts at 8 o’clock.

October noun

Short meaning: the tenth month of the year.

Example: Schools often open in October.

odd adjective

Short meaning: strange or unusual; also describes numbers not divisible by two.

Example: That’s an odd question.

oddly adverb

Short meaning: in a strange or unusual way.

Example: He behaved oddly today.

of preposition

Short meaning: used to show belonging, relation, or what something consists of.

Example: A cup of tea.

off adverb / preposition

Short meaning: away from a place or position; not operating.

Example: Please switch off the light.

offend verb

Short meaning: to make someone upset or annoyed.

Example: I didn’t mean to offend you.

offensive adjective

Short meaning: rude or likely to upset people.

Example: His words were offensive.

offer verb / noun

Short meaning: to present something for someone to accept; also the thing offered.

Example: They offered me a job.

office noun

Short meaning: a place where people work, often at desks.

Example: She works in a law office.

officer noun

Short meaning: someone with an official position, especially in the police or military.

Example: The officer checked our documents.

official adjective / noun

Short meaning: approved by authority; also a person with a public or formal position.

Example: This is the official statement.

officially adverb

Short meaning: in a formal or legally accepted way.

Example: The city was officially declared safe.

often adverb

Short meaning: many times or frequently.

Example: They often travel abroad.

oh exclamation

Short meaning: used to show surprise, understanding, or emotion.

Example: Oh, I didn’t know that!

oil noun

Short meaning: a thick liquid used for cooking, lubrication, or fuel.

Example: Heat the oil before frying.

old adjective

Short meaning: not new; having lived or existed for a long time.

Example: He wore an old jacket.

old-fashioned adjective

Short meaning: not modern; typical of the past.

Example: Some people prefer old-fashioned methods.

on preposition / adverb

Short meaning: touching or supported by something; happening.

Example: The book is on the table.

once adverb / conjunction

Short meaning: one time; at a past time; as soon as (when used as conjunction).

Example: I visited Paris once.

one number / pronoun / determiner

Short meaning: the number 1; a single person or thing.

Example: Only one student was late.

one another pronoun

Short meaning: used to show mutual action among three or more people.

Example: The team members support one another.

onion noun

Short meaning: a round vegetable with layers, used in cooking.

Example: Chop the onion finely.

online adjective / adverb

Short meaning: connected to the internet or taking place on the internet.

Example: The course is available online.

only adverb / adjective / conjunction

Short meaning: no more than; just; the single one.

Example: She has only two days left.

onto preposition

Short meaning: moving to a position on something.

Example: The cat jumped onto the roof.

open verb / adjective

Short meaning (verb): to move something so it is not closed.

Example: Please open the window.

Short meaning (adjective): not shut; available.

Example: The shop is open now.

opening noun

Short meaning: the beginning of something; a hole or space; a job opportunity.

Example: The opening of the film is exciting.

openly adverb

Short meaning: in an honest and public way without hiding.

Example: She spoke openly about her concerns.

operate verb

Short meaning: to make a machine or system work; to perform a medical surgery.

Example: He operates heavy machinery.

operation noun

Short meaning: a medical procedure; or an organized activity or process.

Example: The heart operation was successful.

opinion noun

Short meaning: a personal belief or judgment about something.

Example: In my opinion, the movie was excellent.

opponent noun

Short meaning: a person you compete or fight against.

Example: She defeated her opponent in the final match.

opportunity noun

Short meaning: a chance to do something.

Example: This job is a great opportunity for you.

oppose verb

Short meaning: to disagree with or fight against something.

Example: Many people oppose the new law.

opposed adjective

Short meaning: completely against or not agreeing with something.

Example: They are firmly opposed to the proposal.

opposing adjective

Short meaning: competing or fighting against each other.

Example: The opposing teams prepared for the final match.

opposite adjective / noun / preposition

Short meaning: completely different; facing something; on the other side.

Example: The bank is opposite the post office.

opposition noun

Short meaning: strong disagreement or resistance.

Example: There was strong opposition to the plan.

option noun

Short meaning: something you can choose from different possibilities.

Example: You have two options: stay or leave.

or conjunction

Short meaning: used to show a choice between possibilities.

Example: Tea or coffee?

orange noun / adjective

Short meaning (noun): a round citrus fruit.

Example: She ate an orange for breakfast.

Short meaning (adjective): describing the color orange.

Example: He wore an orange shirt.

order noun / verb

Short meaning (noun): a request for goods; arrangement; command.

Short meaning (verb): to ask for something to be made, supplied, or delivered.

Example: They placed an order online.

ordinary adjective

Short meaning: normal and usual; not special.

Example: It was just an ordinary day.

organ noun

Short meaning: a part of the body that has a special purpose.

Example: The heart is an important organ.

organization noun

Short meaning: a group formed for a particular purpose.

Example: She works for an international organization.

organize verb

Short meaning: to arrange or plan something carefully.

Example: They organized a meeting for Monday.

organized adjective

Short meaning: arranged or planned in a neat and effective way.

Example: She is very organized at work.

origin noun

Short meaning: the beginning, source, or cause of something.

Example: The origin of the tradition is unknown.

original adjective / noun

Short meaning (adj): existing from the beginning; not a copy.

Short meaning (noun): the first version of something.

Example: The original painting is priceless.

originally adverb

Short meaning: at first; in the beginning.

Example: The project was originally planned for May.

other adjective / pronoun / determiner

Short meaning: different from the one already mentioned.

Example: Do you have any other questions?

otherwise adverb

Short meaning: if not; in a different way.

Example: You must hurry, otherwise you'll miss the bus.

ought to modal verb

Short meaning: used to say what is the right or sensible thing to do.

Example: You ought to apologize.

ounce noun

Short meaning: a unit of weight equal to 28 grams.

Example: The recipe needs an ounce of butter.

our determiner

Short meaning: belonging to us.

Example: This is our home.

ours pronoun

Short meaning: something that belongs to us.

Example: The blue house is ours.

ourselves pronoun (reflexive)

Short meaning: the reflexive form of “we.”

Example: We built the shed ourselves.

out adverb / preposition

Short meaning: not inside; away from a place.

Example: She went out for a walk.

outdoor adjective

Short meaning: happening or used outside.

Example: They enjoy outdoor activities.

outdoors adverb

Short meaning: outside; not inside a building.

Example: They ate lunch outdoors.

outer adjective

Short meaning: on the outside; external.

Example: The outer walls were painted blue.

outline noun / verb

Short meaning (noun): the main ideas or structure of something.

Short meaning (verb): to describe something briefly and clearly.

Example: The teacher gave an outline of the lesson.

output noun

Short meaning: the amount of something produced or the information a system gives.

Example: The factory increased its output this year.

outside adverb / noun / preposition / adjective

Short meaning: not inside; on or to the outer part of something.

Example: The kids are playing outside.

outstanding adjective

Short meaning: extremely good; clearly noticeable.

Example: She did an outstanding job on the project.

oven noun

Short meaning: a heated appliance used for baking or cooking food.

Example: Put the cake in the oven for 30 minutes.

over preposition / adverb

Short meaning: above or across something; finished; more than a number or amount.

Example: The plane flew over the city.

overall adjective / adverb

Short meaning: in general; including all details or effects.

Example: Overall, the results were positive.

overcome verb

Short meaning: to successfully deal with a problem or difficulty.

Example: She overcame her fear of heights.

overseas adjective / adverb

Short meaning: in or to a foreign country across the sea.

Example: She studied overseas for two years.

owe verb

Short meaning: to need to pay or give something to someone.

Example: You owe me $10.

own verb / adjective

Short meaning (verb): to have something as your property.

Short meaning (adj): belonging to a particular person.

Example: She owns a small business.

owner noun

Short meaning: a person who owns something.

Example: The owner of the restaurant was very friendly.

own up phrasal verb

Short meaning: to admit that you did something wrong.

Example: He finally owned up to breaking the window.