980+ Words that Start With O | Popular O Words

Words that Start With O! In this lesson, you will learn a list of commonly used words starting with O in English with ESL pictures to help you enhance your English vocabulary.

Table of Contents

Words that Start With O

2 Letter Words that Start with O

3 Letter Words that Start with O

4 Letter Words that Start with O

Oath
Obey
Odds
Odor
Oily
Okay
Omen
Omit
Once
Only
Onto
Onus
Onyx
Oops
Ooze
Open
Opus
Oral
Otto
Ouch
Ours
Oust
Oval
Oven
Over
Owed

5 Letter Words that Start with O

Oakum
Oasis
Oaten
Oater
Obeah
Obeli
Obese
Objet
Occur
Ocean
Ocher
Ochre
Ocker
Ocrea
Octad
Octal
Octet
Octyl
Oddly
Odeon
Odeum
Odium
Odour
Offal
Offer
Often
Ogham
Ogive
Oiled
Oiler
Okapi
Olden
Older
Oldie
Oleic
Olein
Oleum
Olive
Ology
Ombre
Omega
Oncet
Onion
Onlay
Onset
Ontic
Oomph
Ootid
Opera
Opine
Opium
Opsin
Optic
Orach
Oracy
Orang
Orate
Orbit
Order
Oread
Organ
Oribi
Oriel
Orlop
Ormer
Orris
Ortho
Oscar
Osier
Osmic
Ossia
Ostia
Other
Ottar
Otter
Ought
Ounce
Ousel
Outdo
Outer
Outgo
Outre
Ouzel
Ovary
Ovate
Overt
Ovine
Ovoid
Ovolo
Ovule
Owing
Owlet
Owned
Owner
Owsen
Oxbow
Oxeye
Oxide
Oxids
Oxime
Oxims
Oxlip
Oxter
Ozone

6 Letter Words that Start with O

Oafish
Object
Oblast
Oblate
Oblige
Oblong
Obsess
Obtain
Obtuse
Occult
Occupy
Ocelot
Octane
Octave
Octavo
Octopi
Ocular
Oculus
Oddity
Odious
Oedema
Oeuvre
Offend
Office
Offing
Offish
Offset
Oilman
Okayed
Oldest
Oleate
Olefin
Omelet
Online
Onrush
Onside
Onward
Oocyst
Oocyte
Oodles
Oolite
Oolong
Oompah
Oozing
Opaque
Opener
Openly
Operon
Opiate
Opioid
Oppose
Optics
Optima
Option
Oracle
Orange
Orator
Orchid
Ordain
Ordeal
Ordure
Orgasm
Orient
Origin
Oriole
Ormolu
Ornate
Ornery
Orphan
Orrery
Osmium
Osmose
Osprey
Ossify
Ostium
Ostler
Ostomy
Otiose
Otitis
Ouster
Outage
Outbid
Outbox
Outcry
Outdid
Outfit
Outfly
Outfox
Outhit
Outing
Outlaw
Outlay
Outlet
Output
Outran
Outrun
Outset
Outwit
Overdo
Overly
Ovonic
Owlish
Owning
Oxford
Oxtail
Oxygen
Oyster

7 Letter Words that Start with O

Oatmeal
Obelisk
Obesity
Obliged
Obligor
Oblique
Obscene
Obscure
Observe
Obverse
Obviate
Obvious
Oceanic
Octagon
October
Octopus
Oddball
Odds-on
Odorous
Odyssey
Oedipal
Offbeat
Offence
Offense
Offhand
Officer
Offline
Offload
Offside
Oilseed
Olivine
Olympic
Omicron
Ominous
Omnibus
Onboard
Oneness
Onerous
Oneself
Ongoing
On-hand
Onshore
Onstage
On-time
Onwards
Oohlala
Opacity
Open up
Opening
Operand
Operant
Operate
Opinion
Oppress
Optical
Optimal
Optimum
Opulent
Oration
Oratory
Orbital
Orbiter
Orchard
Orderly
Ordinal
Oregano
Organdy
Organic
Organon
Orifice
Origami
Orotund
Oscular
Osmosis
Ostrich
Ottoman
Outback
Outcast
Outcome
Outcrop
Outdone
Outdoor
Outface
Outflow
Outgrew
Outgrow
Outlast
Outlier
Outline
Outlive
Outlook
Outpace
Outplay
Outpost
Outrace
Outrage
Outrank
Outsail
Outsell
Outside
Outsize
Outward
Ovarian
Ovation
Overage
Overall
Overdue
Overjoy
Overlap
Overlay
Overpay
Overran
Overrun
Oversaw
Oversee
Overuse
Oxidant
Oxidase
Oxidize

8 Letter Words that Start with O

Obdurate
Obedient
Obeisant
Obituary
Obligate
Obliging
Oblivion
Observer
Obsessed
Obsidian
Obsolete
Obstacle
Obstruct
Occasion
Occupant
Occupied
Occurred
Odorless
Offender
Offering
Official
Offshoot
Offshore
Offstage
Ointment
Olympiad
Olympian
Omission
On-board
Oncogene
Oncology
Oncoming
Onlooker
Onscreen
Ontology
Openness
Operable
Operatic
Operator
Operetta
Opponent
Opposite
Optimism
Optimist
Optimize
Optional
Opulence
Ordinary
Ordinate
Ordnance
Organism
Organist
Organize
Orgasmic
Oriental
Oriented
Original
Ornament
Orthodox
Osculate
Ossified
Outboard
Outbound
Outbrave
Outbreak
Outburst
Outclass
Outdance
Outdated
Outdoors
Outdrive
Outfield
Outgoing
Outhouse
Outlying
Outmoded
Outpoint
Outreach
Outright
Outscore
Outshine
Outshone
Outsider
Outsmart
Outstrip
Outthink
Outweigh
Overbold
Overcame
Overcast
Overcoat
Overcome
Overdone
Overdose
Overflow
Overfond
Overhang
Overhaul
Overhead
Overhear
Overheat
Overkill
Overlaid
Overland
Overleaf
Overload
Overlook
Overlord
Overpass
Override
Overrode
Overrule
Overseas
Overseen
Overseer
Oversize
Overtake
Overtime
Overtook
Overture
Overturn
Overview
Overwork
Oxymoron

9 Letter Words that Start with O

Obcordate
Obedience
Obeisance
Obfuscate
Objectify
Objection
Objective
Obligated
Oblivious
Obnoxious
Obscenity
Obscurity
Observant
Obsession
Obsessive
Obstetric
Obstinacy
Obstinate
Obtrusive
Obviously
Occipital
Occlusion
Occlusive
Occultism
Occupancy
Octagonal
Oddsmaker
Oestrogen
Offensive
Offertory
Officiate
Officious
Offscreen
Offspring
Olfaction
Olfactory
Oligarchy
Oligopoly
Ombudsman
Oncogenic
One-liner
Onslaught
On-target
Open-mind
Operating
Operation
Operative
Ophiolite
Opportune
Optometry
Orangutan
Orchestra
Ordinance
Organized
Orgiastic
Orientate
Originate
Orphanage
Orthodoxy
Orthotics
Oscillate
Osteopath
Ostracism
Ostracize
Otherness
Otherwise
Ourselves
Outdoorsy
Outermost
Outerwear
Outfitted
Outgrowth
Outlander
Outnumber
Outrigger
Outskirts
Outsource
Outspoken
Outspread
Outsprint
Outwardly
Ovenproof
Overblown
Overboard
Overbuild
Overdraft
Overdrive
Overeager
Overjoyed
Overnight
Overpower
Overprint
Overrated
Overreach
Overreact
Oversexed
Overshoot
Oversight
Overspend
Overspill
Overstate
Overstock
Overtaken
Overthrow
Overwhelm
Overwrite
Oviparous
Ownership
Oxacillin
Oxidation
Oxycodone
Oxygenase
Oxygenate

10 Letter Words that Start with O

Obediently
Obligation
Obligatory
Obligingly
Obliterate
Obnubilate
Obsequious
Observable
Observance
Obstetrics
Obtainable
Occasional
Occidental
Occupation
Occurrence
Oceanarium
Oceanfront
Oceangoing
Oceanology
Ochlocracy
Octahedral
Octahedron
Oculomotor
Oesophagus
Officially
Oftentimes
Okey-dokey
Oldfangled
Oleaginous
Oligoclase
Oligopsony
Olivaceous
Omnipotent
Omniscient
Omnivorous
Onomastics
Opalescent
Open-ended
Openhanded
Operculate
Ophthalmia
Ophthalmic
Opposition
Oppression
Oppressive
Opprobrium
Optimistic
Orangewood
Oratorical
Orchardist
Ordinarily
Ordination
Ordonnance
Organicism
Organology
Originally
Ornamental
Ornithopod
Ornithosis
Oropharynx
Orthoclase
Orthogonal
Osculation
Osmolality
Osmolarity
Ostensible
Ostensibly
Osteoblast
Osteoclast
Osteogenic
Osteopathy
Otherwhere
Otherworld
Outbalance
Outcompete
Outfielder
Outlandish
Outpatient
Outperform
Outpouring
Outrageous
Outstation
Outstretch
Ovariotomy
Overactive
Overbought
Overburden
Overcharge
Overcommit
Overexpose
Overextend
Overflight
Overgrowth
Overjoying
Overmaster
Overmighty
Overmodest
Overpraise
Overriding
Overshadow
Oversimple
Overspread
Overstrain
Overstress
Overstride
Oversupply
Overtaking
Overweight
Overwinter
Ovipositor

11 Letter Words that Start with O

Objectively
Objectivism
Objectivity
Observation
Observatory
Obsolescent
Obstruction
Obviousness
Occultation
Occupancies
Octagonally
Octahedrons
Octapeptide
Odontoblast
Odoriferous
Odorousness
Oecumenical
Offenseless
Offensively
Offertories
Offhandedly
Officialdom
Officialese
Officialism
Officiaries
Officiating
Officiation
Officiously
Offprinting
Offscouring
Olfactories
Oligarchies
Oligochaete
Oligoclases
Oligopolies
Ominousness
Omnifarious
Omnipotence
Omnipotents
Omnipresent
Omniscience
Oncogenesis
Oneiromancy
On-the-ball
On-the-beam
Ontogenesis
Ontological
Open-handed
Openhearted
Open-minded
Operational
Opinionated
Opportunist
Opportunity
Opprobrious
Optometrist
Orchestrate
Orientalize
Orientation
Originality
Origination
Originative
Ornithology
Ornithopter
Orthocenter
Orthodontia
Orthography
Orthopedics
Orthopteran
Orthoscopic
Orthostatic
Oscillation
Oscillogram
Ostensorium
Ostentation
Osteoplasty
Ostracoderm
Outbreeding
Outbuilding
Outdistance
Outdoorsman
Outmaneuver
Outsourcing
Outstanding
Ovariectomy
Overachieve
Overanxious
Overarching
Overbalance
Overbearing
Overcareful
Overcasting
Overcorrect
Overdevelop
Overexcited
Overfatigue
Overflowing
Overgarment
Overindulge
Over-joyful
Overnighter
Overproduce
Overprotect
Overstretch
Overweening
Overwhelmed
Overwrought
Overzealous
Oxalacetate
Oxyhydrogen
Ozonosphere

12 Letter Words that Start with O

Obfuscations
Objectifying
Objectivisms
Objectivists
Objurgations
Oblanceolate
Oblatenesses
Obligatorily
Obligingness
Obliterating
Obliteration
Obliterative
Obliterators
Obnubilating
Obnubilation
Obscurantism
Obscurantist
Obscurations
Observations
Obsolescence
Obsoleteness
Obstetrician
Obstreperous
Obstructions
Obstructives
Obtusenesses
Occasionally
Occupational
Oceanography
Octogenarian
Octosyllable
Officeholder
Officialdoms
Officialeses
Officialisms
Officiations
Offishnesses
Offscourings
Oleaginously
Oleandomycin
Oleoresinous
Olfactometer
Oligarchical
Oligochaetes
Oligophagies
Oligophagous
Oligopsonies
Oligotrophic
Omnipotences
Omnipotently
Omnipresence
Omnisciences
Omnisciently
Omnivorously
Oncornavirus
Onomatopoeia
On-the-money
Onychophoran
Oophorectomy
Open-hearted
Opinionative
Optimization
Orchestrated
Orchidaceous
Organisation
Organization
Organoleptic
Orienteering
Orthodontics
Orthogenesis
Orthographic
Orthopteroid
Orthorhombic
Orthotropous
Oscillograph
Oscilloscope
Ossification
Ostentatious
Osteogenesis
Osteomalacia
Osteoplastic
Osteoporosis
Osteosarcoma
Otherworldly
Otosclerosis
Outperformed
Outplacement
Overachiever
Overbrimming
Overcapacity
Overcautious
Overcritical
Overestimate
Overfamiliar
Overgenerous
Overinflated
Overmedicate
Overpersuade
Overpopulate
Overpowering
Overpressure
Overregulate
Oversimplify
Overwhelming
Overwithhold
Oxaloacetate
Oxyacetylene

13 Letter Words that Start with O

Objectionable
Old-fashioned
On-the-button
Opportunities
Outperforming
Outstandingly
Overcommitted
Overconcerned
Overconfident
Overconscious
Overconstruct
Overconsuming
Overcorrected
Overcredulous
Overdecorated
Overdecorates
Overdemanding
Overdependent
Overdesigning
Overdeveloped
Overdirecting
Overdiscounts
Overdiversity
Overdocuments
Overeagerness
Overeducating
Overeducation
Overelaborate
Overembellish
Overencourage
Overenergetic
Overengineers
Overestimated
Overestimates
Overexpanding
Overexpansion
Overexplained
Overpromising
Overpromoting
Overprotected
Overreactions
Overregulated
Overregulates
Overreliances
Overreporting
Overresponded
Oversaturated
Oversaturates
Oversecretion
Oversensitive
Overseriously
Overservicing
Overshadowing
Overslaughing
Overtightened
Overtreatment

14 Letter Words that Start with O

Open-heartedly
Organizational

Learn more about list of words that start with n in English.

Words that Start with O | Examples

He was very respectful at home and obedient to his parents.
Try to be objective if you want to spend your money wisely.
Facts can be established by observation and experiment.
The role of scientists is to observe and describe the world, not to try to control it.
The police are trying to obtain a more accurate picture of crime levels.
Men were standing around, swilling beer and occasionally leering at passing females.
The highest spring tides of the year occur after the equinoxes in March and September.
The students return in October for the start of the new academic year.
There have been several retirements in my office recently.
Most software programs allow you to compose emails offline.
The older generation prefer a darker and more traditional kind of clothing.
In desperation, Mrs. Jones submitted to an operation on her right knee to relieve the pain.
You must avail yourself of every opportunity to speak English.
We will lay stress on industrial structure optimization while using FDI.
The well-known singer was accompanied at the electronic organ by his school teacher.
The organization is ever vigilant for threats to the habitats of birds.
Tableware for outdoor use should ideally be unbreakable.
The overall cost of the exhibition was ￡400,000.
To make a lasting marriage we have to overcome self-centeredness.
That city has decided to do away with overhead wires.
The welfare of a child should always override the wishes of its parents.
We’ve just appointed a coordinator who will oversee the whole project.
Pulling out to overtake, the car collided head-on with a van.
The document provides a general overview of the bank’s policies.
She said insensitive things to the overweight woman.
The owner has offered a reward for the recovery of the stolen goods.