Countable Nouns That Start with O and End with S
Explore 103 verified English countable nouns starting with O and ending with S, including Oops, Optics, Oasis, Outskirts, Octopus, Overalls and Opus. Sort these count nouns with singular and plural forms by word length for ESL grammar practice, determiner usage, and plural spelling below, or review singular and plural count rules in our noun grammar guide.
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Starts with OA
1 words oasis
Starts with OB4 words
obsequies
oblateness
obelus
obliquus
Starts with OC5 words
octopus
oculus
ocellus
occipitofrontalis
octonarius
Starts with OD
2 words oddness
odontornithes
Starts with OF
2 words offhandedness
offendress
Starts with OG
1 words ogress
Starts with OL
2 words olympics
olecranarthritis
Starts with OM5 words
omnibus
ombuds
omnishambles
omphalos
omphalodes
Starts with ON9 words
onus
oncovirus
onomatopoiesis
onychocryptosis
oncornavirus
onos
oneirocritics
onychitis
oncus
Starts with OO
2 words oops
oodles
Starts with OP15 words
optics
opus
optimates
ophrys
opisthotonos
opponens
opinicus
ophites
opulus
opisthodomos
ophthalmomycosis
ophthalmodiagnosis
ophthalmomyositis
ophthalmoneuritis
ophthalmorrhexis
Starts with OR19 words
orthotics
organogenesis
orris
organophosphorus
orbicularis
orchardgrass
orchis
orthosis
orogenesis
organometallics
ornithorhynchus
oratress
ornis
orthomyxovirus
orthros
orexis
orchiepididymitis
orthoaxis
orthrosanthus
Starts with OS10 words
oscars
osmosis
os
osteonecrosis
osteomyelitis
osmanthus
osteoarthrosis
osteopetrosis
osteoclasis
ostleress
Starts with OT
1 words otocinclus
Starts with OU6 words
outskirts
outgoings
ouroboros
outcross
outpass
oubaas
Starts with OV15 words
overalls
overpass
overemphasis
overdress
overdiagnosis
overanalysis
overstress
overclass
overplus
overtrousers
overfocus
ovibos
ovotestis
overpress
overkindness
Starts with OW
1 words owens
Starts with OX
1 words oxalis
Starts with OZ
2 words ozonolysis
ozothamnus