Nouns That Start With O

Here we have a list of Nouns that start with O. You will learn the most commonly used nouns in the English language to expand your vocabulary in writing/speaking. Nouns Start with O will help you to learn about some of the most interesting events, emotions, and common things starting with the letter ‘O’.

What Are Nouns Beginning with O?

A noun is a word that commonly functions as the name of a distinct object or group of things, such as a person, place, living creatures, places, actions, qualities, states of existence, or ideas.

Person: Olivia, Owen, Optometrist

Place: Osaka, Ontario, Opera House

Thing: Oven, Oar, Origami, Ocarina

Explore More: Nouns That Start with P

List of Nouns That Start With O

Oliver	Organism	Overthrow
Occupation	Overlap	Overcoat
Obligation	Oppression	Outcry
Official	Oracle	Ordination
Opportunity	Onion	Oesophagitis
Operation	Odour	Olive
Opposition	Organiser	Oval
Officer	Orbit	Overdose
Oxford	Oscar	Ornament
Organization	Obsession	Occupancy
Opinion	Outrage	Orient
Organization	Obedience	Overhaul
Offer	Obstacle	Op
Output	Omission	Overdrive
Option	Ordeal	Oblivion
Object	Outsider	Onus
Occasion	Offender	Outlay
Owner	Outlet	Occupant
Outcome	Original	Obscurity
Offense	Oct	Octave
Ownership	Outside	Observance
Objective	Offensive	Observatory
Origin	Outing	Obesity
Observation	Orchard	Optic
Ocean	Overall	Obscenity
Oxygen	Otto	Oyster
Observer	Obstruction	Orchid
Operator	Oesophagus	Opium
Orchestra	Ore	Oligonucleotide
Opponent	Openness	Occult
Outline	Objectivity	Old
Organ	Overtime	Organizer
Oven	Oxide	Oral
Ozone	Ordnance	Organist
Objection	Occupier	Otter
Orange	Orthodoxy	Outflow
Outlook	Offeror	Ovation
Owl	Obituary	Over
Occurrence	Outburst	Ox
Oz	Overdraft	Op
Orientation	Ounce	Oxidation
Outset	Onslaught	Ollie
Outbreak	Ombudsman	Omeprazole
Offspring	Overflow	Originator
Opposite	Originality	Orgasm
Overview	Orc	Orphanage
Optimism	Open	Octopus
Outfit	Opener	Oversight
Onset	Os	Overhead
Ord	Outpatient	Overture
Omen	Overhang	Orfe
Omi	Oscillator	Operative
Orphan	Ovum	Optimality
Oscillation	Otherness	Obsidian
Oddity	Overseer	Ohm
Orgy	Occlusion	Operetta
Obe	Onlooker	Ontology
Outcrop	Obiter	Ola
Overload	Optician	Omnipotence
Ordinance	Obstinacy	Outgrowth
Omnibus	Octreotide	Orifice
Odyssey	Ornithology	Obstetrician
Opt-out	Ordinariness	Obliteration
Oratory	Outlaw	Osprey
Oboe	Okapi	Overproduction
Omega	Orchestration	Optimization
Orb	Ornamentation	Oilseed
Opus	Oeuvre	Ouija
Outcast	Ornithologist	One-year-old
Odeon	Offing	Outpouring
Octamer	Octagon	Od
Oedema	Oriel	Og
Ostrich	Overspill	Ogre
Omelette	Out-patient	Offworlder
Oxon	Oilfield	Oddness
Offshoot	Opulence	Onyx
Officialdom	Overkill	Oblong
Oestrogen	Optimization	Oxo
Ointment	Opal	Opportunist
Off-licence	Offal	Orthography
Ode	Oneness	Opiate
Ordinary	Ob	Ostentation
Offset	Orang-utan	Oddball
Outbound	Ochre	Oregano
Outreach	Oversimplification	Oncology
Osteoporosis	Osmosis	Oligo
Overlord	Outfall	Overwork
Opportunism	Outback	Orogeny
Operand	Obs	Override
Overgrowth	Om	Orderliness
Oligarchy	Opacity	Overcapacity
Ovulation	Orf	Overlordship
One-off	Orderly	Oratorio
Outpost	Obverse	Omer
Orator	Outhouse	Outfield
Objector	Ovary	Overpopulation
Oda	Oxidase	Oe
Optimist	Otaku	Oldman

A Full List of Nouns That Begin With O

Obsolescence	Ooze	Oblast
Objectification	Obelisk	Oppressor
Obfuscation	Osh	Orthoptera
Octane	Objectivist	Ogee
Orang	Olympiad	Oilcloth
Oleate	Outturn	Ordure
Orienteering	Obduracy	Ouzo
Ostracism	Once-over	Oodles
Optimum	Origination	Oxidization
Obex	Overuse	Outspokenness
Outsole	Outa	Obscurantist
Oestrus	Overestimate	Octet
Oligopoly	Oca	Orefield
Overgrazing	Outbuilding	Occurrence
Obeisance	Origami	Offspinner
Olf	Osmolality	Outage
Odium	Overtype	Ossification
Overpayment	Ostinato	Oomph
Oscilloscope	Ostler	Obscurantism
Okra	Outboard	Overbridge
Oration	Obviousness	Over-consumption
Ophthalmology	Oviduct	Obsequies
Otitis	Ouster	Objectivism
Overtone	Ovipositor	Ontogeny
Orbital	Ophiolite	One-liner
Overstatement	Oncogene	Origo
Orangery	Out-of-doors	Obstructionism
Offeree	Oralism	Osteonecrosis
Orientalism	Osteoarthritis	Odorant
Omniscience	Ophthalmologist	Otherworld
Oilskin	Oryx	Order
Oceanography	Orbiter	Ost
Off-chance	Osteopath	Orangerie
Oliva	Organza	Opossum
Overshoot	Oximetry	Omnipresence
Outremer	Olsalazine	Overthrust
Oystercatcher	Overaccumulation	Omnium
Opprobrium	Oxtail	Obbligato
Oliphant	Organon	Overreaction
Orthopaedics	One-upmanship	Oracy
Overrun	Oxygenation	Outer
Omicron	Operculum	Outmigration
Oldie	Overexpression	Onomatopoeia
Ordo	Octavo	Oxyhaemoglobin
Orogen	Orangutan	Outplacement
Off-season	Ogle	Oligomer
Olivine	Openside	Offertory
Overcast	Occultation	Omnipotent
Ottoman	Orca	Oxytocin
Okay	Osteopathy	Ordinate
Ormolu	Onrush	Outrider
Oligodendrocyte	Ort	Overstimulation
Orvieto	Outlawry	Out-tray
Overbalance	Oliguria	Osteospermum
Obloquy	Oversteer	Organdie
Opioid	Oolite	Operon
Oculist	Outfitter	Ossuary
Obtuseness	Oche	Odalisque
Oggy	Offense	Ontogenesis
Osmium	Ology	Ovine
Ottar	Offensiveness	Out
Osmolarity	Oppo	Ogi
Oblique	Open-mindedness	Oba
Occultism	Optoelectronics	Orientalist
Oocyte	Oppositeness	Ocker
Orchestrator	Osmometer	Overcharge
Octahedron	Odometer	Okada
Obit	Obliquity	Orogenesis
Oranda	Operability	Oxbow
Overestimation	Okay	Overinvolvement
Orgone	Oestradiol	Onchocerciasis
Overlooker	Org	Oppositionist
Overmantel	Out-relief	Occultist
Oiliness	Out-turn	Orosomucoid
Oilman	Orris	Organophosphate
Overindebtedness	Oceanographer	Operant
Overdetermination	Oik	Oesophagectomy
Ovoid	Offchance	Oncoprotein
Occiput	Overexploitation	Oubliette
Overtrousers	Octavius	Odontoid
One-piece	Optimiser	Omerta
Overemphasis	Oleander	Ouguiya
Oralist	Overindulgence	Oceanarium
Orality	Organogenesis	Oul
Oboist	Oxy	Offtake
Orrery	Optometrist	Oidium
Owre	Oiticica	Orang-outang
Organicist	Oxyacetylene	Organelle
Old-timer	Overtreatment	Outperformance
Overexertion	Overdraught	Off-worlder
Orgel	Opacification	Offcut
Ocelot	Ower	Overexposure
Occidental	Oncologist	Orangutang
Ordinand	Overarm	Outgroup
Overdevelopment	One-sidedness	Onanism
Outrigger	Obstructionist	Overfishing
Orthogenesis	O Noun	Overflight
Octogenarian	Orchestre	Outro

Nouns Starting With Alphabet O

Oka	Oleoyl	Omnivore
Optronics	Omphalos	Origanum
Overreach	Octopussy	Obdurateness
Ophthalmoscope	Opalescence	Openmindedness
Ouzel	Outliner	Outlands
Overspecialization	Opaline	Outdatedness
Oppressiveness	Owings	Ouvrier
Occupance	Obstructiveness	Orzo
Oriole	Omentum	Obeche
Overvaluation	Overlayer	Officiousness
Oprichnina	Oxygenase	Office
Overcommitment	Otherworldliness	Oper
Opaqueness	Operationalization	Oth
Oesophagogastroduodenoscopy	Orchis	One-nighter
On	Operatorship	Oncogenesis
Oxidant	Oximeter	Obliqueness
Oligarch	Overplus	Obliquus
Overconfidence	Ornamenter	Ovalbumin
Outerwear	Outport	Oxfendazole
Osteosarcoma	Overexpansion	Osteomalacia
Outfielder	Oculus	Olfaction
Organum	Orthopyroxene	Overrepresentation
Oompah	Obscuration	Osteomyelitis
Octapeptide	Oversupply	Overstability
O Noun	Ogam	Owlet
Oversubscription	Otolaryngology	Ozokerite
Oxymoron	Ocarina	Oncovin
Opticals	Obsequiousness	O Noun
Ortho	Oxocarbon	Ondansetron
Outstation	Oloroso	Obnoxiousness
Orangeade	Oilbird	Operationalism
Osha	Oldness	Orthophosphate
Over-excitement	O Noun	Oscillograph
Overfamiliarity	Outswinger	Olivet
Outrageousness	Oviposition	Obol
Outer	Oxyrhynchus	Overconsumption
Offerer	Occident	Okrug
Oppidum	Overdependence	Ossia
Oblate	Outcaste	Overstrike
O Noun	Open-handedness	O Noun
Obsessiveness	Oblation	Osculation
Obligatoriness	Otoscopy	Ornamentalism
Optometry	Open-side	Olla
Otalgia	Overprotection	Overwrap
Officialese	Overactivity	Ommatidium
O Noun	Oversensitivity	Osier
Ostmark	Oxalis	Over taxation
Opticks	Ostracization	Overman
Oner	Oribi	Oiler
Omnicompetence	Outbreeding	Oldster

100+ Popular Nouns That Start With O

20+ Common Nouns That Start with O

Here is a list of common ‘o’ nouns:

• Ocean: Vast expanse of water.
• Office: Workplace for tasks.
• Oven: Appliance for baking.
• Orange: Citrus fruit.
• Octopus: Marine creature.
• Opera: Musical performance.
• Oasis: Desert water source.
• Orbit: Celestial path.
• Oar: Rowing implement.
• Onion: Vegetable with layers.
• Opal: Gemstone with iridescence.
• Organ: Body tissue.
• Oval: Rounded shape.
• Owl: Nocturnal bird.
• Oil: Liquid for cooking.
• Obstacle: Hurdle to overcome.
• Orchestra: Musical ensemble.
• Outlet: Power source.
• Oyster: Shellfish delicacy.
• Obelisk: Tall, four-sided pillar.

List of Abstract Nouns That Start with O

Abstract nouns are intangible concepts, ideas, or emotions that evoke feelings and cannot be perceived through the five senses. Examples include love, happiness, and justice.

Here is a list of Abstract O Nouns:

• Observation: Act of closely watching or examining.
• Optimism: Positive outlook or belief in good outcomes.
• Opulence: Display of great wealth or luxury.
• Organization: Structured arrangement or coordinated effort.
• Originality: Quality of being novel or unique.
• Outcome: Result or consequence of an action.
• Obligation: Binding duty or commitment.
• Opacity: State of being impenetrable to light.
• Opinion: Personal belief or judgment about something.
• Order: Arrangement or sequence of elements.
• Oblivion: State of being forgotten or unknown.
• Orbit: Path of a celestial object around another.
• Openness: Quality of being receptive or transparent.
• Overflow: Excess or spilling over a limit.
• Ovation: Enthusiastic public applause or acclaim.

Related:

Baby Names That Start With O

Positive Words Start With O

Adjectives That Start With O

List of Abstract Nouns That Start with O

Abstract nouns are intangible concepts, ideas, or emotions that evoke feelings and cannot be perceived through the five senses. Examples include love, happiness, and justice.

Here is a list of Abstract O Nouns:

• Observation: Act of closely watching or examining.
• Optimism: Positive outlook or belief in good outcomes.
• Opulence: Display of great wealth or luxury.
• Organization: Structured arrangement or coordinated effort.
• Originality: Quality of being novel or unique.
• Outcome: Result or consequence of an action.
• Obligation: Binding duty or commitment.
• Opacity: State of being impenetrable to light.
• Opinion: Personal belief or judgment about something.
• Order: Arrangement or sequence of elements.
• Oblivion: State of being forgotten or unknown.
• Orbit: Path of a celestial object around another.
• Openness: Quality of being receptive or transparent.
• Overflow: Excess or spilling over a limit.
• Ovation: Enthusiastic public applause or acclaim.

List of Popular Positive Nouns Start with O

Here is a list of Positive O Nouns with definitions:

Optimism

• Meaning: Positive outlook or belief in a favorable outcome.
• Synonym: Hopefulness
• Antonym: Pessimism

Opportunity

• Meaning: A favorable chance or circumstance.
• Synonym: Chance
• Antonym: Obstacle

Overflow

• Meaning: Abundance or excess of something positive.
• Synonym: Abundance
• Antonym: Scarcity

Oneness

• Meaning: Unity and harmony.
• Synonym: Unity
• Antonym: Division

Openness

• Meaning: Willingness to accept new ideas or experiences.
• Synonym: Receptiveness
• Antonym: Closed-mindedness

Originality

• Meaning: Creativity and uniqueness.
• Synonym: Creativity
• Antonym: Conformity

Optimality

• Meaning: The state of being the best possible.
• Synonym: Excellence
• Antonym: Mediocrity

Oasis

• Meaning: A place of peace, relief, or happiness.
• Synonym: Sanctuary
• Antonym: Desolation

Outstanding

• Meaning: Exceptionally good or impressive.
• Synonym: Exceptional
• Antonym: Mediocre

Overachievement

• Meaning: Excelling beyond expected levels.
• Synonym: Excelling
• Antonym: Underachievement

Overflowing

• Meaning: Filled to the brim with positivity.
• Synonym: Abundant
• Antonym: Depleted

Overture

• Meaning: An introduction or proposal indicating positive intentions.
• Synonym: Proposal
• Antonym: Refusal

Ownership

• Meaning: The state of possessing something.
• Synonym: Possession
• Antonym: Lack

Onwardness

• Meaning: The quality of moving forward positively.
• Synonym: Progress
• Antonym: Stagnation

Ovation

• Meaning: Enthusiastic applause or approval.
• Synonym: Applause
• Antonym: Criticism

Open-heartedness

• Meaning: Generosity and sincerity in feelings.
• Synonym: Generosity
• Antonym: Stinginess

Outpouring

• Meaning: A spontaneous expression of positive emotion.
• Synonym: Expression
• Antonym: Restraint

Overjoy

• Meaning: Extreme happiness or delight.
• Synonym: Elation
• Antonym: Despair

Opulence

• Meaning: Great wealth and luxury.
• Synonym: Luxury
• Antonym: Poverty

Obligingness

• Meaning: Willingness to assist or accommodate.
• Synonym: Helpfulness
• Antonym: Reluctance

15+ List of Proper Nouns That Start with O

Proper nouns with O are specific names of unique entities, such as individuals, places, or organizations, always capitalized to distinguish them from common nouns.

• Osaka
• Olivia
• Olympus
• Oakley
• Oman
• Ontario
• Oprah
• Orlando
• Oxford
• Osaka Castle
• Oceanic Airlines
• Oliver Twist
• Oklahoma City
• Oreo
• Oak Ridge

List Of Collective Nouns That Start With O

Here is a list of Collective O-nouns with meaning:

• Orchestra: A group of musicians playing instruments.
• Organization: A collective of people with a common purpose.
• Outfit: A set of clothing or equipment.
• Oscillation: A movement back and forth.
• Opulence: Wealth and luxury.
• Oasis: A fertile area in a desert.
• Oven: An enclosed cooking appliance.
• Oncology Team: Medical specialists treating cancer.
• Occasion: A particular event or ceremony.
• Observer Corps: A group monitoring and reporting.
• Overload: Excessive load or burden.
• Order: An organized arrangement or sequence.
• Outlay: Expenditure or investment.
• Outfield: The area in baseball beyond the bases.
• Office: A place of business or administration.

FAQs (Nouns Starting with O)

What are some nouns starting with O?

Nouns starting with O include objects like ocean, orchestra, opera, and office, and names such as Olivia, Oliver, and Olympics.

What are some positive nouns that start with O?

Positive nouns starting with O include optimism, opportunity, outlook, originality, and oasis, fostering positivity and growth.

What are nouns beginning with the consonant O?

Nouns beginning with O include ocean, orchestra, owl, office, opera, olive, origami, octopus, orchid, oasis, and orange.

What’s the name of a famous person whose name starts with O?

Oprah Winfrey, an influential media mogul, philanthropist, and talk show host, is a famous person whose name starts with the letter O.

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