Home » List of 285 Nouns That Start with O with Definitions and Examples

List of 285 Nouns That Start with O with Definitions and Examples

by Tim

How about introducing you all to the nouns that start with O? Doesn’t this sound like a great idea? If yes, then congratulations, because we are going to bring nouns that start with O to your doorstep.

This article will surely get you hooked because we have tried our best to assemble a bunch of those nouns starting with O that are not just commonly used but are very popular also.

For your ease, we have divided this article into various sections that include common, proper, and kindergarten nouns and some other sections as well. You are going to become familiar with the nouns beginning with O really soon.  

Nouns form the basic structure of our sentence because they act as a subject or an object and without them, the basic structure of sentence is lost.

The quick use of proper nouns beginning with O will make you sound more confident and mark an impact on the next person. So, why not rush for this opportunity without any further delay?    

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Common Nouns That Start with O

In this list of nouns that start with O, why not begin with the most common nouns that start with O? We will slowly take this ride from easy and common level to the tricky and adventurous one.

1. Ounce

  • Definition: a unit of weight just like kgs that is equivalent to 28.3 grams
  • Synonyms: speck, particle
  • Example: She was looking chubby as if she has gained an ounce of weight.

2. Outside

  • Definition: the side that is on the external face of something
  • Synonyms: exterior, surface
  • Example: John painted the outside of his house yesterday.

3. Option

  • Definition: a choice that is available to be made
  • Synonyms: choice, alternative
  • Example: She has an open option of leaving this job if she cannot accommodate its harsh timings.

4. Observation

  • Definition: a statement made by noticing someone or something keenly
  • Synonyms: opinion, reflection
  • Example: She has a sense of strong observation and that makes her stand out.

5. Opinion

  • Definition: a personal point of view about someone or something made as a judgement
  • Synonyms: belief, school of thought
  • Example: She has different opinions regarding feminism.

6. Objection

  • Definition: an expression that shows disagreement or opposition to something
  • Synonyms: protest, demurrer
  • Example: People are making strong objections on the recent laws regarding violence.

7. Opening

  • Definition: a space that allows to pass through it, a gateway to go through
  • Synonyms: hole, space
  • Example: I couldn’t see any opening in the pipe.  

8. Offer

  • Definition: a choice to be accepted or denied
  • Synonyms: proposal, suggestion
  • Example: She is being given heavy offers of social media manager.

9. Origin

  • Definition: a point that initiates the arrival of something, from where something is derived
  • Synonyms: start, genesis
  • Example: The origin of this city is still a secret everyone is in search of.  

10. Occasion

  • Definition: an event or happening that happens particularly as planned
  • Synonyms: instance, moment
  • Example: Her grand birthday party seems like a great occasion of this month.

Positive Nouns That Start with O

Let’s now become acquainted with the positive nouns that start with O to make fresh and positive use of vocabulary in our daily conversation. Positive nouns depict a useful feature or quality of something and that makes us curious about them. So why not hush this curiosity right now?

1. Occupation

  • Definition: a person’s profession or job in which he has remained engaged
  • Synonym: profession, trade
  • Example: His father’s occupation is that of a retired general from the army.

2. Output

  • Definition: something gained as a result of putting something in, an end result
  • Synonyms: production, product
  • Example: The output was exactly what was expected.  

3. Oath

  • Definition: takeover of some control by making a divine promise of doing justice to your service
  • Synonyms: vow, promise
  • Example: Her father took an oath of chief justice of the supreme court last week.

4. Oration

  • Definition: a speech or sermon delivered in formal events
  • Synonyms: address, speech
  • Example: The honorable guest has arrived for oration in the hall.

5. Obedience

  • Definition: consent to follow someone’s order
  • Synonyms: compliance, acquiescence
  • Example: He was living in obedience to society’s laws.

6. Oomph

  • Definition: a personality of attraction or full of energy
  • Synonyms: potency, vigor
  • Example: She has an oomph that attracts everyone to her.

7. Opportunity

  • Definition: a possible situation or chance to avail
  • Synonyms: chance, luck
  • Example: She got an opportunity of working as a content writer for a renowned brand.

8. Objective

  • Definition: a thing aimed at or sought
  • Synonyms: goal, target
  • Example: Their company has achieved its objective.

9. Ovation

  • Definition: applause by the audience after some entertaining show
  • Synonyms: endorsement, cheer
  • Example: The show received a strong ovation from the audience.

10. Outing

  • Definition: a trip arranged for the sake of entertainment
  • Synonyms: picnic, trip
  • Example: I won’t be working today as I am going for an outing.

Nouns That Start with O for Kindergarten

Nouns that start with the letter O at the kindergarten level include those nouns that are very basic and frequently used. The common use of these nouns automatically illustrates the significance that we are going to depict here.   

1. Oven

  • Definition: a machine that is used to heat up the meal
  • Synonyms: stove, microwave
  • Example: She put the meal in oven to heat it.   

2. Oil

  • Definition: a viscous liquid that is used as a fuel
  • Synonyms: lubricant, fuel
  • Example: She has mistakenly put the wrong oil in her car. 

3. Ocean

  • Definition: a sea area that is divided on a large scale
  • Synonyms: deep sea, water waves
  • Example: She sat in silence and gazed at the waves in the ocean.

4. Oar

  • Definition: a blade containing stick that assists in moving a boat in the water
  • Synonyms: paddle, propeller
  • Example: He used oars to make the boat float smoothly over the water.

5. Oxygen

  • Definition: a gas that is taken inside and used in breathing
  • Synonyms: atom, gas
  • Example: In her last moments, she suffered a shortage of oxygen.

6. Organ

  • Definition: part of the body that performs an important function
  • Synonyms: tissue, body part
  • Example: Many organs are being transplanted easily now.

7. Office

  • Definition: a place where official work is being done
  • Synonyms: workroom, studio
  • Example: She is very happy after getting an easy office job.

8. Oat

  • Definition: a cereal plant that is grown in cold weather and used for feeding animals
  • Synonyms: gruel, grout
  • Example: Fields of oats are getting destroyed due to heavy rainfall.

9. Onion

  • Definition: a round-shaped vegetable that has an eye-burning effect
  • Synonyms: vegetable, Allium Cepa
  • Example: He owns three fields of onion crops. 

10. Olive

  • Definition: small oval-shaped fruit often green and black in color used in different foods.
  • Synonyms: olive oil, plant
  • Example: She was scattering olives on the pizza bread.

Nouns That Start with O to Describe a Person

How to describe a person with nouns that start with O? You don’t know the answer? Hold on, not anymore. Because we are going to provide you with a satisfactory answer so that you don’t get speechless next time. Let’s discuss the nouns that start with O to describe a person.

1. Officer

  • Definition: a person that some kind of authority, a term associated with commission or forces mostly
  • Synonyms: officeholder, deputy
  • Example: He got appointed as a CSP officer in his own city.

2. Organizer

  • Definition: a person who organizes or arranges an event
  • Synonyms: arranger, planner
  • Example: Mr. Marvell proved himself as the best event organizer.

3. Owner

  • Definition: a person who owns something as property
  • Synonyms: possessor, holder
  • Example: She is the owner of the two most popular makeup brands. 

4. Overpopulation

  • Definition: a situation where excessive people exist in a place
  • Synonyms: crowdedness, denseness
  • Example: India is taking several steps to control the issue of overpopulation.

5. Outsider

  • Definition: a person who comes from outside
  • Synonyms: stranger, visitor
  • Example: They were not agreeing on taking any outsider in their team.

6. Outlaw

  • Definition: a person who breaks the laws and regulations, one who takes step illegally
  • Synonyms: outcast, exile
  • Example: He was given the title of an outlaw by the courts.

7. Optimist

  • Definition: a person who has a sheer hope of success and is fully motivated
  • Synonyms: dreamer, idealist
  • Example: She is such an optimist that she never loses hope.

8. Ownership

  • Definition: the position of having possession of something
  • Synonyms: possession, hold
  • Example: She got the ownership of her Visa last month.

9. Overseer

  • Definition: a person who leads or commands others (in official work)
  • Synonyms: supervisor, foreman
  • Example: He is appointed as an overseer in this new office.

10. Outcast

  • Definition: a person who got rejected or fired from somewhere
  • Synonyms: rejected, ostracized
  • Example: He was an outcast due to his involvement in some illegal activities.

Nouns That Start with O to Describe a Place

Let us now make you acquainted with the nouns beginning with O to describe a place. Covering all the other categories, we thought of it as essential to introduce you to places as well that start with the letter O so let’s begin.

1. Ottawa

  • Definition: a capital of Canada near the border of the US
  • Synonyms: (none)
  • Example: He bought a house near Ottawa.

2. Orlando

  • Definition: city of Florida known for having many parks
  • Synonyms: (none)
  • Example: Orlando is a very nice place to spend vacations in.  

3. Odessa

  • Definition: a port city of Ukraine that is known for having beaches
  • Synonyms: (none)
  • Example: Odessa is a very beautiful place, especially because of the beaches it owns.

4. Ontario

  • Definition: a province of Canada near the border of the US
  • Synonyms: (none)
  • Example: Ontario is known for having beautiful lakes and spell-bounding mountains.

5. Oviedo

  • Definition: a small town in Spain that is from the times of medieval
  • Synonyms: (none)
  • Example: Oviedo holds a very interesting history of medieval times.

6. Orleans

  • Definition: a city in France near Paris
  • Synonyms: (none)
  • Example: Let’s visit Orleans next month.

7. Oakland

  • Definition: a large city in California holds a Victorian architecture
  • Synonyms: (none)
  • Example: Oakland gives us a picturesque view from Paris.

8. Omaha

  • Definition: city in the US known for its remarkable history
  • Synonyms: (none)
  • Example: Omaha has its name for breweries.

9. Oman

  • Definition: Arabian country in Asia
  • Synonyms: (none)
  • Example: Oman has a location in Arabian Peninsula. 

10. Obihiro

  • Definition: city on island of Hokkaido
  • Synonyms: (none)
  • Example: Obihiro is also known as the homeland of polar bears.

Nouns That Start with O to Describe Things

There are many things that start with O and guess what? We have assembled them all for you right here. You won’t be going for deep research of noun words that start with O to describe things anymore because we will cover you here.  

1. Orange

  • Definition: name of color or a citrus fruit
  • Synonyms: fruit
  • Example: She brought a dozen of oranges and shared them with her little brother.

2. Ointment

  • Definition: a smooth creamy substance rubbed on the skin that relieves pain
  • Synonyms: lotion, cream
  • Example: He was regularly using an ointment on his wounds.

3. Orchid

  • Definition: a plant that belongs to Orchidaceae family
  • Synonyms: plant
  • Example: Orchids are required to be grown in shallow soil.

4. Overcoat

  • Definition: a long coat that serves as a warm blanket or a layer of paint 
  • Synonyms: raincoat, parka
  • Example: He wore an overcoat in the frizzy nights of December.

5. Outfit

  • Definition: a costume or dress worn by someone
  • Synonyms: dress, suit
  • Example: She was wearing a famous designer’s outfit at her birthday party.

6. Oatmeal

  • Definition: food that is made from oats
  • Synonyms: gruel, cereal
  • Example: She was having oatmeal after so long.

7. Ohmmeter

  • Definition: a measuring instrument used for measuring current
  • Synonyms: measuring device, instrument
  • Example: Amount of current was constantly being recorded in the ohmmeter.

8. Opal

  • Definition: a type of stone that is derived from Silica
  • Synonyms: gem, jewel
  • Example: The jewelry contained opals and pearls in it.

9. Ornament

  • Definition: a little thing used for making something look more eye-catching
  • Synonyms: knick-knack, trinket
  • Example: She brought beautiful flowers to keep in her room as an ornament.

10. Ovary

  • Definition: small oval glands in female body on both sides of uterus
  • Synonyms: (none)
  • Example: She is diagnosed as having stones in her ovaries.

Nouns That Start with O to Describe Animals

Animals with O nouns need to be mentioned after other categories. We have collected ten nouns with letter O to describe animals that are easy to learn and never forgettable.

1. Octopus

  • Definition: an aquatic animal from the Octopoda specie
  • Synonyms: (none)
  • Example: She was very excited to see octopus for the first time in her life.

2. Opossum

  • Definition: a Didelphimorphia specie found mostly in America
  • Synonyms: (none)
  • Example: Opossums are known to hate garlic.  

3. Ostrich

  • Definition: the largest bird on earth
  • Synonyms: (none)
  • Example: Many more Ostriches were added in the zoo.

4. Orca

  • Definition: a type of whale that belongs to dolphin family
  • Synonyms: (none)
  • Example: Orcas are beautiful whales that are the largest member of dolphin family.

5. Okapi

  • Definition: a giraffe found in forests that has a zebra like appearance
  • Synonyms: (none)
  • Example: Okapi is known to be the last living member of Giraffe family.

6. Orangutan

  • Definition: form of apes that lives in Indonesia and Malaysia
  • Synonyms: (none)
  • Example: Orangutan is an animal that lives in rainforests.

7. Owl

  • Definition: birds that have strong vision
  • Synonyms: (none)
  • Example: Over 200 species of owls are known to exist.

8. Otter

  • Definition: mammals that feed on plants and live on water and land both
  • Synonyms: (none)
  • Example: Otter has a short body with long tail.

9. Ocelot

  • Definition: a wild and light cat  
  • Synonyms: (none)
  • Example: Ocelots are known as the most active animals at night. 

10. Oyster

  • Definition: specie of mollusks that is the family of salt-water animals
  • Synonyms: (none)
  • Example: Oyster has heart and other internal organs that create pain.

Proper Nouns That Start with O

Proper nouns that start with O are needed to be known by everyone. Ask me why? Because they are of paramount significance. Proper nouns are required to be known properly besides pronounced properly. So, let’s have a look at proper nouns that begin with O.

1. Oliver

  • Definition: a male name
  • Synonyms: (none)
  • Example: Oliver stalked her for hours.

2. Oldsmobile

  • Definition: an automobile brand in America known for General Motors
  • Synonyms: (none)
  • Example: This car seems like an Oldsmobile.

3. Osaka

  • Definition: a company of batteries for motorcycles and cars in Pakistan
  • Synonyms: (none)
  • Example: Batteries of Osaka function exceptionally long than expected.

4. Otto

  • Definition: a male name
  • Synonyms: (none)
  • Example: Otto has a remarkable personality.

5. Oxford

  • Definition: collegiate research university in England
  • Synonyms: (none)
  • Example: She is studying at Oxford.

6. Ordos

  • Definition: a place in Mongolia that is the twelfth subdivision
  • Synonyms: (none)
  • Example: Tourists went to the Ordos for tourism.

7. Oscar

  • Definition: a type of award given to the performer for some achievement
  • Synonyms: (none)
  • Example: She won an Oscar for her latest film pictured on the issue of domestic violence.

8. Omdurman

  • Definition: Sudan’s largest city named after the battle of Omdurman
  • Synonyms: (none)
  • Example: She hails from Omdurman.

9. Osella

  • Definition: a racing car that originated in Italy
  • Synonyms: (none)
  • Example: They were using Osella for a racing competition this year.

10. Olivia

  • Definition: a brand that offers hair dyes and has its name from Olivia trees
  • Synonyms: (none)
  • Example: Olivia is a well-known brand for hair coloring at an affordable cost.

Nouns That Start with O – Full List (285 Words)

So yeah, we have provided you with nouns that start with O as we promised in the very beginning of this article. Here is an elaborate list of nouns that start with O.

  • Ounce
  • Outside
  • Option
  • Observation
  • Opinion
  • Objection
  • Opening
  • Offer
  • Origin
  • Occasion
  • Oliver
  • Oldsmobile
  • Osaka
  • Otto
  • Oxford
  • Ordos
  • Oscar
  • Omdurman
  • Osella
  • Olivia
  • Occupation
  • Output
  • Oath
  • Oration
  • Obedience
  • Oomph
  • Opportunity
  • Objective
  • Ovation
  • Outing
  • Oven
  • Oil
  • Ocean
  • Oar
  • Oxygen
  • Organ
  • Office
  • Oat
  • Onion
  • Olive
  • Officer
  • Organizer
  • Owner
  • Overpopulation
  • Outsider
  • Outlaw
  • Optimist
  • Ownership
  • Overseer
  • Outcast
  • Ottawa
  • Orlando
  • Odessa
  • Ontario
  • Oviedo
  • Orleans
  • Oakland
  • Omaha
  • Oman
  • Obihiro
  • Orange
  • Ointment
  • Orchid
  • Overcoat
  • Outfit
  • Oatmeal
  • Ohmmeter
  • Opal
  • Ornament
  • Ovary
  • Octopus
  • Opossum
  • Ostrich
  • Orca
  • Okapi
  • Orangutan
  • Owl
  • Otter
  • Ocelot
  • Oyster
  • Organization
  • Orchestra
  • Overexploitation
  • Opener
  • Onyx
  • Outset
  • Overcrowding
  • Oaf
  • Oxytetracycline
  • Outline
  • Offense
  • Orb
  • Oblige
  • Obliteration
  • Organdy
  • Ode
  • Obsidian
  • Oilseed
  • Oversight
  • Overrun
  • Onslaught
  • Opprobrium
  • Overhang
  • Octagon
  • Occupant
  • Outlook
  • Observer
  • Overhaul
  • Objector
  • Omnivore
  • Oratorio
  • Oleomargarine
  • Opposite
  • Oxcart
  • Overcast
  • Overall
  • Ome
  • Orbit
  • Orphanage
  • Oracle
  • Outpost
  • Offspring
  • Orientation
  • Odyssey
  • Observance
  • Openness
  • Opera
  • Operator
  • Oxide
  • Organification
  • Outcry
  • Overestimate
  • Oilcloth
  • Outrage
  • Object
  • Oubliette
  • Ordnance
  • Opposition
  • Onset
  • Oscillator
  • Official
  • Obstacle
  • Outlet
  • Outlawry
  • Osmium
  • Oscillation
  • Obloquy
  • Orgone
  • Organist
  • Outflow
  • Outlay
  • Obligation
  • Oiticica
  • Outpouring
  • Oral
  • Orchestrator
  • Ox
  • Opiate
  • Overture
  • Ordinary
  • Onlooker
  • Original
  • Octoroon
  • Ooh
  • Oodles
  • Obeisance
  • Ordinance
  • Overweight
  • Octavia
  • Obsession
  • Offersey
  • Outbreak
  • Ouster
  • Overflow
  • Ozone
  • Order
  • Oasis
  • Orthicon
  • Omnibus
  • Officialdom
  • Overtime
  • Optimization
  • Obverse
  • Orthography
  • Orphan
  • Olympian
  • Oppression
  • Orthophosphate
  • Omnipotence
  • Occurrence
  • Offal
  • Overprotection
  • Ophelia
  • Operetta
  • Operation
  • Overpressure
  • Oblivion
  • Opponent
  • Opium
  • Onrush
  • Objectivity
  • Oxalate
  • Outfield
  • Optimum
  • Oxidation
  • Outhouse
  • Outburst
  • Overhead
  • Overnight
  • Ogre
  • Oneupmanship
  • Ordeal
  • Omnipotent
  • Owi
  • Opus
  • Orchestration
  • Ornamentation
  • Omen
  • Offshoot
  • Oak
  • Opportunism
  • Outpatient
  • Outfielder
  • Operand
  • Offering
  • Overestimation
  • Oklahoma
  • Overload
  • Outgrowth
  • Ossification
  • Obstruction
  • Overthrow
  • Origination
  • Ornamental
  • Ornithology
  • Omelet
  • Oval
  • Opulence
  • Oligarchy
  • Offender
  • Omission
  • Orgasm
  • Obelisk
  • Ocher
  • Ooze
  • Occupancy
  • Obesity
  • Orchard
  • Oratory
  • Octahedron
  • Ostracism
  • Ochre
  • Oathe
  • Outcome
  • Oceanography
  • Optimality
  • Overlay
  • Orthodontist
  • Oblong
  • Osteopathy
  • Offing
  • Occlusion
  • Optimism
  • October
  • Oiliness
  • Orderly
  • Originality
  • Orgy
  • Outreach
  • Obscenity
  • Oboist
  • Outback
  • Ocarina
  • Obscurity
  • Obstructionist
  • Organism
  • Open
  • Oep
  • Objectification
  • Overpayment
  • Odor
  • Oversimplification
  • Originator
  • Orator
  • Oxen

Final Thoughts on Nouns That Start with O

After giving you a bunch of nouns that start with O, I must ask about your experience of giving this article a good read and valuable time. I bet you are not regretting it because we tried our best to make it easier for you all.

Nouns that start with O are not just these nouns that we have covered in this article but many more as well.

But due to the limitation of length and time and besides this, not letting it get boring for you guys, we have just mentioned a handful of nouns beginning with O.

We will keep our ritual of bringing many more nouns and modern vocabulary to the ground for you all. Hopefully, this list of nouns starting with O was beneficial to you.

And in return we want your promise to be on our side forever. Enjoy your time and will meet you in the next more knowledgeful article. Goodbye!

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