222 Nouns that Start with O in English

Are you looking for a list of nouns that start with O? Actually, there are many words that start with O in the English language. Don’t fret, though. We don’t expect you to merely take these words for it. Instead, stick around and read on to the next section. It is a list containing various nouns starting with the letter O.

Nouns That Start with O

What Are Nouns That Start With O?

O isn’t necessarily a letter that people think about words starting with. In fact, you might believe there aren’t many nouns, verbs, or adjectives that begin with the fifteenth letter of the alphabet. However, there are many nouns that start with O, some common examples include ocean, octopus, onion, opera, office, oven, orchid, orb, oyster, and observatory.

Nouns That Start with O Pin

Common Nouns That Start with O

Nouns Examples
Oak The oak tree was more than 300 years old.
Oar He used an oar to paddle the boat.
Oasis The oasis provided a much-needed respite from the desert heat.
Oat The farmer planted oats in the field to feed his livestock.
Oath He took an oath to tell the truth in court.
Obelisk The obelisk stood tall in the city square.
Object She picked up the object and examined it closely.
Obligation It’s my obligation to take care of my elderly parents.
Observation Through careful observation, she was able to identify the bird species.
Observatory The observatory was equipped with state-of-the-art telescopes.
Obstacle The fallen tree was an obstacle in our path.
Occasion We dressed up for the special occasion.
Occupation His occupation was a firefighter.
Ocean The ocean stretched out before them, vast and blue.
Octave The song was written in a high octave.
Octopus The octopus changed colors to blend in with its surroundings.
Odor The odor coming from the trash can was unbearable.
Offense The team’s offense was too strong for the opposing team to handle.
Office She worked in a busy office downtown.
Officer The police officer pulled over the speeding car.
Official The official announcement was made at a press conference.
Oil The car needed an oil change.
Okra She fried the okra until it was crispy and golden brown.
Olive The salad was garnished with slices of ripe green olives.
Omen The black cat crossing their path was seen as an omen of bad luck.
Onset The onset of winter brought cold temperatures and snow.
Opera The opera was a grand production with elaborate costumes and sets.
Operation The surgical operation was a success.
Operator The phone operator connected the call to the correct department.
Opinion Everyone is entitled to their own opinion.
Opportunity She saw the job opening as an opportunity to advance her career.
Opposition The opposition party had different ideas on how to run the country.
Option The menu had a vegetarian option.
Orange The orange was juicy and sweet.
Orbit The satellite was in a stable orbit around the earth.
Orchestra The orchestra played a beautiful symphony.
Order She placed an order for a pizza with extra cheese.
Ordinary The day was just an ordinary day, nothing special happened.
Organ The organ was the largest instrument in the church.
Organization The organization was dedicated to helping those in need.
Origin The origin of the custom is shrouded in mystery.
Ornament The tree was decorated with colorful ornaments for the holidays.
Orphan The orphan was taken in by a kind-hearted family.
Ostrich The ostrich is the largest bird in the world.
Other The others in the group were all doctors, but he was a lawyer.
Otter The playful otter swam in the pond.
Outcome The outcome of the election was surprising to many people.
Outlet She plugged the lamp into the electrical outlet.
Oval The track for the race is an oval that measures 400 meters in length.
Oven She baked a batch of cookies in the oven.
Owl The owl hooted softly in the night.
Owner The owner of the store greeted customers with a smile.
Ox The oxen pulled the heavy cart up the hill.
Oxygen The doctor gave her a dose of oxygen to help her breathe.

Abstract Nouns That Start with O

Nouns Examples
Objectivity The news should be reported with objectivity and impartiality.
Oblivion The famous singer fell into oblivion after his scandalous behavior.
Obscurity The author’s work remained in obscurity until it was discovered years later.
Observation The scientist made a careful observation of the behavior of the monkeys.
Occasion The wedding was a joyous occasion for the whole family.
Odyssey The book tells the story of an epic odyssey across the ocean.
Offense The athlete apologized for his unintentional offense against the other team.
Offering The churchgoers brought offerings to the altar during the service.
Offspring The proud parents watched as their offspring graduated from college.
Oneness The spiritual leader spoke about the importance of achieving a sense of oneness with the universe.
Openness The manager encouraged an atmosphere of openness and honesty in the workplace.
Opportunity The scholarship provided an opportunity for the student to attend college.
Opposition The two political parties are in opposition on many issues.
Optimism Despite the setbacks, the team maintained an optimistic outlook for the future.
Option The menu offered a vegetarian option for those who did not eat meat.
Order The waiter took our order and brought us our food promptly.
Organization The nonprofit organization worked to provide aid to those in need.
Orientation The new employees received an orientation to the company’s policies and procedures.
Originality The artist’s work was praised for its originality and creativity.
Outcome The outcome of the experiment was unexpected and surprising.
Outrage The community expressed outrage at the injustice committed against the victim.
Outset The project faced challenges from the outset but was ultimately successful.
Ownership The company claimed ownership of the intellectual property rights to the software.

RelatedAbstract Nouns

Positive Nouns That Start with O

Noun Examples
Oasis The oasis provided a much-needed refuge from the desert heat.
Oblivion He drank to oblivion and forgot all his problems.
Obsession His obsession with fitness led him to become a personal trainer.
Occasion The wedding was a joyous occasion for all who attended.
Ocean The ocean was calm and peaceful, with the sun setting over it.
Odyssey The epic Odyssey took the hero through many trials and tribulations.
Offering The church collected offerings to support the local community.
Offspring The proud parents showed off their offspring to all their friends.
Omega The omega represents the end of something and the beginning of something else.
Oneness The philosophy of yoga emphasizes the oneness of body and mind.
Opal She wore a beautiful opal necklace that sparkled in the light.
Openness The company’s culture encouraged openness and honesty among its employees.
Opulence The hotel was known for its opulence and luxury amenities.
Oracle The oracle predicted that the king would be victorious in battle.
Orbit The satellite was placed in a geostationary orbit around the earth.
Order The judge issued an order for the defendant to pay restitution to the victim.
Orgasm The couple experienced intense pleasure during their simultaneous orgasm.
Origin The origin of the universe is a subject of great scientific debate.
Ornament The Christmas tree was adorned with beautiful ornaments and lights.
Ovation The audience gave the performer a standing ovation for his outstanding performance.
Overcomer The cancer patient was an overcomer who refused to let the disease beat her.
Overflow The river experienced an overflow during the heavy rain, causing flooding in the nearby areas.
Overjoyment The young child was filled with overjoyment on Christmas morning.
Ownership The ownership of the company changed hands after a hostile takeover.
Oxymoron “Jumbo shrimp” is an example of an oxymoron, where two opposite words are used together.

Proper Nouns That Start with O

  • Obama
  • Ohio
  • Oklahoma
  • Olympus
  • Oman
  • Oprah
  • Orange County
  • Oregon
  • Orlando
  • Osaka
  • Oslo
  • Oxford
  • Oxfam
  • Oreo
  • Oakley
  • Oakland
  • Occidental College
  • Ocean City
  • Ocean Spray
  • Oceania
  • Odyssey
  • Othello
  • Ozark
  • Ozaukee County
  • Ozzy Osbourne

List of Nouns that Start with O

  • Oak
  • Oasis
  • Oath
  • Oathe
  • Oatmeal
  • Obedience
  • Obelisk
  • Obesity
  • Object
  • Objectification
  • Objection
  • Objective
  • Objectivity
  • Objector
  • Obligation
  • Oblige
  • Obliteration
  • Oblivion
  • Oboist
  • Obscenity
  • Obscurity
  • Observance
  • Observation
  • Observer
  • Obsession
  • Obsidian
  • Obstacle
  • Obstructionist
  • Obverse
  • Ocarina
  • Occasion
  • Occlusion
  • Occupancy
  • Occupant
  • Occupation
  • Occurrence
  • Ocean
  • Oceanography
  • Ocelot
  • Ocher
  • Ochre
  • Octahedron
  • Octoroon
  • Odor
  • Odyssey
  • Oep
  • Offal
  • Offender
  • Offense
  • Offer
  • Offering
  • Offersey
  • Office
  • Officer
  • Official
  • Officialdom
  • Offing
  • Offspring
  • Ohio
  • Oil
  • Oilcloth
  • Oilheating
  • Oilseed
  • Ointment
  • Oiticica
  • Okra
  • Oleomargarine olive
  • Ome
  • Omelet
  • Omen
  • Omission
  • Ommission
  • Omnipotence
  • Oneupmanship
  • Onion
  • Onlooker
  • Onrush
  • Onset
  • Onslaught
  • Ooh
  • Ooze
  • Open
  • Opener
  • Opening
  • Opera
  • Operand
  • Operation
  • Operator
  • Operetta
  • Opinion
  • Opium
  • Opponent
  • Opportunism
  • Opportunity
  • Opposite
  • Opposition
  • Oppression
  • Opprobrium
  • Optimality
  • Optimism
  • Optimization
  • Optimum
  • Option
  • Oracle
  • Oration
  • Orator
  • Oratorio
  • Oratory
  • Orb
  • Orbit
  • Orchard
  • Orchestra
  • Orchestration
  • Ordeal
  • Order
  • Ordering
  • Orderly
  • Ordinance
  • Ordinary
  • Ordnance
  • Organ
  • Organdy
  • Organification
  • Organism
  • Organist
  • Organization
  • Orgasm
  • Orgone
  • Orgy
  • Orientation
  • Origin
  • Original
  • Originality
  • Origination
  • Ornament
  • Ornamentation
  • Orphan
  • Orphanage
  • Orthicon
  • Orthodontist
  • Orthography
  • Orthophosphate
  • Oscillation
  • Oscillator
  • Osmium
  • Ossification
  • Ostracism
  • Otter
  • Ounce
  • Ouster
  • Outback
  • Outbreak
  • Outburst
  • Outcast
  • Outcome
  • Outcry
  • Outfield
  • Outfielder
  • Outfit
  • Outflow
  • Outgrowth
  • Outhouse
  • Outing
  • Outlaw
  • Outlawry
  • Outlay
  • Outlet
  • Outline
  • Outlook
  • Outpatient
  • Outpost
  • Outpouring
  • Output
  • Outrage
  • Outreach
  • Outset
  • Outside
  • Outsider
  • Oval
  • Ovation
  • Oven
  • Overall
  • Overcast
  • Overcoat
  • Overcrowding
  • Overestimation
  • Overexploitation
  • Overflow
  • Overhang
  • Overhaul
  • Overhauling
  • Overhead
  • Overheating
  • Overlay
  • Overload
  • Overnight
  • Overpayment
  • Overpopulation
  • Overpressure
  • Overprotection
  • Overriding
  • Overrun
  • Overseer
  • Oversight
  • Oversimplification
  • Overthrow
  • Overtime
  • Overture
  • Overweight
  • Owl
  • Owner
  • Ownership
  • Owning
  • Oxalate
  • Oxcart
  • Oxen
  • Oxidation
  • Oxide
  • Oxygen
  • Oxytetracycline
  • Oyster
  • Ozone

Nouns that Start with O with Meanings


Obviously, nouns that start with O come in many different shapes and sizes. Oak is a short three-letter word and is the name of a tree. Not only that but the noun can be used to describe the wood from an oak tree as well.


Music buffs, we are not talking about the band Oasis, although, that is a noun too. The oasis that’s being referred to here is a fertile area in a dry region. Those who find such places often never want to leave because they’re beautiful, calming, and relaxing.


Ohio is only one of fifty states in the United States. It isn’t a small spot, either, so you’ve likely heard the name before. Research reveals that Ohio features an area of 44,825 square miles. It was home to a population of 11.80 million in 2020. However, that number very well could have increased by now, and why wouldn’t it have? People flock to this location for reasons like the weather, the Pro Football Hall of Fame, and the Rock and Roll Hall of Fame.


Next up on this list of nouns that start with O is the word office. An office is a place where people go to perform work duties. This is usually at a location other than their houses, but those who have remote jobs sometimes have home offices as well.


The okra plant creates long edible beaked pods. This type of food can be eaten alone, as some people enjoy it fried. Meanwhile, others add okra to dishes such as gumbo or vegetable stew.

Some Last Thoughts

So, as you can see, there are plenty of nouns that start with O. The ones listed here barely even begin to scratch the surface. If you want to learn about others, type in a few keywords and perform a Google search. Or are you not about technology? That’s fine. Head to the library or get out that dusty dictionary on the bookshelf and see what you can find.

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