Delving into the world of nouns that start with the letter ‘O’ is a fascinating linguistic journey. These nouns offer a diverse and vibrant range of meanings, each bringing its unique flavor to the English language.
From objects found in nature to abstract concepts, the letter ‘O’ introduces us to a world full of opportunities for exploration and learning. Embracing the variety and depth these nouns provide enriches our vocabulary and enhances our understanding of language’s beauty and complexity.
Nouns That Start With O
| Oligocene | Olf |
| Outpost | Outflow |
| October | Ordeal |
| Outfit | Opera |
| Overhang | Openness |
| Oakland | Opal |
| Owl | Offensive |
| Officialism | Opinion |
| Opportunity | Overall |
| Opposite | Omnipotent |
| Oleosity | Oilcloth |
| Omnipotence | Oklahoma |
| Output | Overture |
| Observance | Ottawa |
| Outgrowth | Omnivore |
| Offence | Oleamen |
| Oxcart | Oceanography |
| Onlooker | Obeisance |
| Overload | Obsession |
| Octahedron | Opener |
| Outcry | Offal |
| Oligarch | Oblige |
| Ochre | Orphan |
| Oblivion | Observation |
| Offension | Olive |
| Ozone | Oldish |
| Oathe | Oxygen |
| Offshoot | Officialdom |
| Oldster | Offer |
| Oblong | Outlet |
| Official | Ogre |
| Organdy | Octagon |
| Oligosiderite | Offendress |
| Originator | Offspring |
| Ostrich | Outpouring |
| Originality | Oleoptene |
| Outreach | Overthrow |
| Offense | Olefine |
| Operation | Overcrowding |
| Orbit | Oracle |
| Ordnance | Omelet |
| Oatmeal | Oboist |
| Orphanage | Object |
| Officer | Operator |
| Overrun | Oleander |
| Oleone | Objection |
| Offing | Ooh |
| Occupation | Obliteration |
| Overcoat | Octoroon |
| Origination | Oval |
| Omission | Oligoclase |
| Orgone | Optimum |
| Oleoresin | Optimist |
| Outset | Obelisk |
| Offering | Offertory |
| Onslaught | Opium |
| Olfactory | Onrush |
| Objector | Oxytetracycline |
| Orthography | Oligarchy |
| Officialty | Operand |
| Olympian | Officialily |
| Octavia | Obloquy |
| Omnibus | Opening |
| Ossification | Optimization |
| Off-Chance | Orchestration |
| Overnight | Orgasm |
| Offscum | Onion |
| Oxalate | Objectification |
| Overweight | Organ |
| Orange | Odyssey |
| Oyster | Obverse |
| Ome | Outlook |
| Oaf | Orgy |
| Occasion | Oscar |
| Overpayment | Outpatient |
| Offerture | Oversimplification |
| Olivenite | Order |
| Olea | Ointment |
| Outfield | Oman |
| Ornamental | Oratorio |
| Officiator | Outing |
| Overflow | Officiant |
| Organism | Oleaster |
| Olfactor | Outlawry |
| Objective | Overcast |
| Oleate | Orchestrator |
| Osaka | Oiliness |
| Ornament | Oubliette |
| Obesity | Obsidian |
| Offlet | Occupancy |
| Ocelot | Olecranon |
| Obscurity | Olfaction |
| Oomph | Oasis |
| Oiticica | Oleograph |
| Outcome | Oldness |
| Offender | Omen |
| Ophelia | Operetta |
| Owner | Observer |
| Orb | Overpopulation |
| Oliva | Oligarchist |
| Olivia | Olio |
| Ordinary | Orthodontist |
| Odor | Ocean |
| Obscenity | Origin |
| Ovation | Oleandrine |
| Oliban | Organization |
| Orchestra | Olein |
| Onset | Off-Ramp |
| Outcast | Oneupmanship |
| Owi | Otter |
| Orchard | Organification |
| Oscillation | Ooze |
| Organist | Opus |
| Offcut | Ouster |
| Outbreak | Orthicon |
| Oxidation | Oration |
| Obligation | Onyx |
| Outlaw | Optimality |
| Overprotection | Objectivity |
| Outburst | Octopus |
| Outside | Oral |
| Orientation | Ornithology |
| Overhaul | Overseer |
| Overestimation | Overestimate |
| Outfielder | Opprobrium |
| Outrage | Organizer |
| Oxen | Oversight |
| Orderly | Offersey |
| Ornamentation | Osteopathy |
| Oilseed | Offset |
| Occlusion | Offscouring |
| Oleomargarine | Oxide |
| Occupant | Outhouse |
| Ode | Oleometer |
| Optimism | Oppression |
| Obstructionist | Oil |
| Oliver | Overlay |
| Ownership | Obstacle |
| Outline | Orator |
| Ocher | Oleaginousness |
| Overpressure | Old |
| Olifant | Overexploitation |
| Orthophosphate | Officeholder |
| Overtime | Outsider |
| Olibene | Office |
| Ounce | Offerer |
| Oep | Off |
| Olibanum | Ox |
| Outlay | Opulence |
| Outback | Obedience |
| Ocarina | Oodles |
| Osmium | Oven |
| Oscillator | Open |
| Overhead | Ordinance |
| Oak | Opiate |
| Opportunism | Obstruction |
| Option | Opponent |
| Opposition | Ommission |
| Original | Oratory |
| Oath | Ostracism |
| Occurrence |
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Nouns That Starting With O
- Oasis
- Meaning: Refuge
- Example: Found water in desert oasis.
- Obligation
- Meaning: Duty
- Example: Fulfilled his obligation promptly.
- Observatory
- Meaning: Watchtower
- Example: Stars viewed from the observatory.
- Occasion
- Meaning: Event
- Example: Dressed up for special occasion.
- Octave
- Meaning: Musical
- Example: Sang in a higher octave.
- Odyssey
- Meaning: Journey
- Example: Life felt like an odyssey.
- Omen
- Meaning: Sign
- Example: Considered the black cat omen.
- Oncology
- Meaning: Medicine
- Example: Specializes in oncology treatment.
- Opaque
- Meaning: Obscure
- Example: The glass was completely opaque.
- Opera
- Meaning: Performance
- Example: Attended a magnificent opera night.
- Opinion
- Meaning: Viewpoint
- Example: Everyone shared their own opinion.
- Opponent
- Meaning: Rival
- Example: Faced a tough opponent today.
- Opportunity
- Meaning: Chance
- Example: Seized a great job opportunity.
- Optimism
- Meaning: Hopefulness
- Example: Maintained optimism despite challenges.
- Orbit
- Meaning: Path
- Example: Earth’s orbit around the sun.
- Orchard
- Meaning: Grove
- Example: Walked through the apple orchard.
- Ordinance
- Meaning: Law
- Example: Abided by city’s new ordinance.
- Oregano
- Meaning: Herb
- Example: Added oregano to the sauce.
- Origin
- Meaning: Source
- Example: Traced back to its origin.
- Ostrich
- Meaning: Bird
- Example: Spotted an ostrich in savannah.
- Outcome
- Meaning: Result
- Example: Pleased with the project’s outcome.
- Outfit
- Meaning: Clothing
- Example: Chose an outfit for party.
- Outlaw
- Meaning: Criminal
- Example: The outlaw evaded capture.
- Outlook
- Meaning: Perspective
- Example: Had a positive life outlook.
- Outpost
- Meaning: Station
- Example: Sent supplies to remote outpost.
- Output
- Meaning: Production
- Example: Increased the factory’s output significantly.
- Outrage
- Meaning: Anger
- Example: News caused widespread public outrage.
- Oval
- Meaning: Shape
- Example: Drew an oval on paper.
- Oven
- Meaning: Appliance
- Example: Baked cookies in the oven.
- Overcoat
- Meaning: Garment
- Example: Wore an overcoat in winter.
- Overdose
- Meaning: Excess
- Example: Risked an overdose of medicine.
- Overhead
- Meaning: Above
- Example: Airplane flew overhead swiftly.
- Overlap
- Meaning: Coincide
- Example: Their schedules often overlap.
- Overload
- Meaning: Burden
- Example: Avoided an overload of work.
- Overpass
- Meaning: Bridge
- Example: Drove over the highway overpass.
- Overture
- Meaning: Introduction
- Example: Enjoyed the symphony’s opening overture.
- Owl
- Meaning: Nocturnal
- Example: Heard an owl at night.
- Ownership
- Meaning: Possession
- Example: Took ownership of new house.
- Oxide
- Meaning: Chemical
- Example: Studied iron oxide properties.
- Oyster
- Meaning: Mollusk
- Example: Ate fresh oysters by sea.
Common Nouns that Start With O
- Ocean – Water
- Oyster – Mollusk
- Olive – Fruit
- Ox – Animal
- Omelet – Food
- Orbit – Path
- Oak – Tree
- Opal – Gemstone
- Orchestra – Ensemble
- Oasis – Refuge
- Ointment – Cream
- Omen – Sign
- Oatmeal – Porridge
- Octagon – Shape
- Outfit – Attire
- Ore – Mineral
- Organ – Instrument
- Orphan – Child
- Outlet – Store
- Oxide – Compound
- Oath – Promise
- Object – Item
- Obligation – Duty
- Observation – Remark
- Occasion – Event
- Occupation – Job
- Oceanography – Study
- Odometer – Gauge
- Odyssey – Journey
- Offense – Crime
- Offering – Contribution
- Office – Workplace
- Offspring – Progeny
- Oil – Lubricant
- Ointment – Salve
- Olive Oil – Liquid
- Omelette – Dish
- Onion – Vegetable
- Opera – Performance
- Opinion – Viewpoint
- Opportunity – Chance
- Opposition – Resistance
- Optimism – Hopefulness
- Option – Choice
- Orange – Citrus
- Orbit – Circle
- Orchestra – Musicians
- Order – Sequence
- Ordinance – Regulation
- Oregano – Herb
Proper Nouns that Start With O
- Orlando – City
- Oscar – Award
- Oxford – University
- Oslo – Capital
- Ontario – Province
- Othello – Play
- Odin – Deity
- Olympus – Mountain
- Orion – Constellation
- Oceania – Region
- Octavia – Name
- O’Keeffe – Artist
- Orwell – Author
- Oahu – Island
- Ohio – State
- Olympia – City
- Opal – Gemstone
- Opera – Artform
- Oracle – Company
- Othello – Character
- Osiris – God
- Olive – Brand
- O’Reilly – Publisher
- Oceana – Organization
- Oriole – Bird
- Oceania – Continent
- Olsen – Surname
- Ozzie – Nickname
- Oberon – King
- Omega – Letter
- Olympiad – Event
- Orpheus – Myth
- Orinoco – River
- Outback – Area
- Oviedo – Town
- Oyster – Bay
- Oklahoma – State
- Ossian – Poet
- Orléans – City
- Osaka – City
- Oceania – Ocean
- Olivier – Actor
- Onassis – Tycoon
- Orient – Express
- Orvieto – Wine
- Ossetia – Region
- Oxbridge – Colleges
- Oahu – Island
- Odyssey – Epic
- Oberlin – College
Positive Nouns That Start With O
- Optimism – Hopefulness
- Opportunity – Chance
- Openness – Transparency
- Originality – Creativity
- Ovation – Applause
- Order – Organization
- Oasis – Refuge
- Offer – Proposal
- Outlook – Perspective
- Oath – Promise
- Obedience – Compliance
- Oneness – Unity
- Overture – Introduction
- Ownership – Possession
- Opulence – Wealth
- Ornament – Decoration
- Ode – Poem
- Oracle – Prophet
- Oblige – Favor
- Objective – Goal
- Obligation – Duty
- Observance – Ritual
- Occasion – Event
- Occupation – Profession
- Offspring – Children
- Open-mindedness – Tolerance
- Opener – Beginning
- Optimum – Best
- Oratory – Eloquence
- Organ – Instrument
- Organization – Structure
- Ornate – Decorative
- Outburst – Expression
- Outdo – Surpass
- Outlet – Release
- Outreach – Extension
- Outset – Start
- Outshine – Eclipse
- Outstanding – Exceptional
- Overture – Prelude
- Ownership – Control
- Oxygen – Air
- Ozone – Layer
- Oomph – Energy
- Opalescence – Shimmer
- Outpouring – Overflow
- Overture – Proposal
- Omnipotence – Power
- Oasis – Haven
- Outperform – Excel
Animals Starting With O
- Orangutan – Primate
- Ostrich – Bird
- Otter – Mammal
- Octopus – Cephalopod
- Owl – Nocturnal
- Ocelot – Feline
- Orca – Whale
- Osprey – Raptor
- Ox – Bovine
- Okapi – Ungulate
- Opossum – Marsupial
- Oryx – Antelope
- Olm – Amphibian
- Oyster – Mollusk
- Oarfish – Fish
- Owl Monkey – Simian
- Ortolan – Songbird
- Oriole – Passerine
- Oscar – Cichlid
- Ocelot Gecko – Lizard
- Oystercatcher – Shorebird
- Ovenbird – Warbler
- Oilbird – Steatornis
- Olingo – Procyonid
- Onager – Equid
- Oarfish – Ribbonfish
- Ochre Sea Star – Echinoderm
- Orange Roughy – Fish
- Opah – Moonfish
- Oogpister Beetle – Insect
Places Starting With O
- Oslo – Capital
- Ohio – State
- Oklahoma – State
- Oman – Country
- Orlando – City
- Oxford – University
- Oahu – Island
- Orleans – City
- Odessa – City
- Ontario – Province
- Otago – Region
- Okinawa – Prefecture
- Olympus – Mountain
- Osaka – City
- Oban – Town
- Ouagadougou – Capital
- Orkney – Archipelago
- Orange – City
- Oviedo – City
- Oulu – City
- Oudtshoorn – Town
- Olathe – City
- Olomouc – City
- Omsk – City
- Ourense – City
- Oswiecim – Town
- Oyster Bay – Hamlet
- Oshawa – City
- Ostend – City
- Outback – Wilderness
Foods Starting With O
- Oats – Grain
- Olive – Fruit
- Oyster – Seafood
- Onion – Vegetable
- Orange – Citrus
- Okra – Pod
- Omelette – Eggdish
- Octopus – Cephalopod
- Orzo – Pasta
- Oxtail – Meat
- Oregano – Herb
- Olive Oil – Dressing
- Oatmeal – Breakfast
- Ossobuco – Italian
- Oysters Rockefeller – Appetizer
- Orangutan – Cocktail
- Oreo – Cookie
- Opah – Fish
- Orange Roughy – Fish
- Oat Milk – Beverage
- Oolong Tea – Drink
- Oatcakes – Snack
- Orecchiette – Pasta
- Ogbono Soup – African
- Oxtail Soup – Soup
- Oyakodon – Japanese
- Oven Chips – Snack
- Oxtail Stew – Stew
- Okroshka – Russian
- Ochazuke – Japanese
Objects Starting With O
- Oar – Paddle
- Obelisk – Monument
- Odometer – Gauge
- Oven – Appliance
- Ornament – Decoration
- Opener – Tool
- Ointment – Cream
- Outlet – Socket
- Organ – Instrument
- Oscilloscope – Device
- Oven Mitt – Protector
- Oilcan – Container
- Ocarina – Flute
- Optical – Lens
- Overcoat – Garment
- Obi – Sash
- Outboard – Motor
- Oblong – Shape
- Overalls – Clothing
- Oximeter – Sensor
- Oyster Knife – Cutlery
- Odometer – Counter
- Overshoe – Footwear
- Ouija – Board
- Orbit Gum – Chewinggum
- Oblate – Disk
- Organza – Fabric
- Opal Ring – Jewelry
- Oarlock – Rowing
- Overskirt – Fashion
Uncountable Nouns With O
- Oxygen – Element
- Ozone – Layer
- Optimism – Hopefulness
- Obedience – Compliance
- Omniscience – Knowledge
- Oregano – Herb
- Opulence – Wealth
- Obscurity – Vagueness
- Oratory – Eloquence
- Overtime – Work
- Outrage – Anger
- Opium – Narcotic
- Orderliness – Neatness
- Oblivion – Forgetfulness
- Originality – Creativity
- Outdoors – Nature
- Ownership – Possession
- Overconfidence – Assurance
- Outlook – Perspective
- Opacity – Density
- Oneness – Unity
- Openness – Frankness
- Obsession – Fixation
- Obedience – Submission
- Offense – Crime
- Omnipotence – Power
- Ostentation – Showiness
- Ornateness – Decoration
- Oversight – Supervision
- Overture – Prelude
