Countable Nouns Starting with O and Containing RO

Browse 96 valid English countable nouns starting with O and containing RO, from Overthrow, Outro, Omicron, Oxymoron, Outgrowth, Oceanfront and Overground to rarer terms. Check definitions and spelling below, or visit our noun grammar guide to review singular and plural count rules.

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Starts with OC6 words
oceanfront
octahedron
octoroon
octroi
occipitofrontalis
octakishexahedron
Starts with OD
1 words
odorophore
Starts with OF
1 words
offeror
Starts with OL5 words
oligodendrocyte
oligodendroglioma
oloroso
oligochrome
oligochronometer
Starts with OM4 words
omicron
ombrophile
ombrometer
ombrophobe
Starts with ON5 words
oneirocritic
oneiromancer
oneirocritics
oneirodynia
oneiroscopist
Starts with OO3 words
oophorosalpingectomy
oophoron
oophorocystectomy
Starts with OP4 words
operon
operosity
ophiuroid
ophthalmotropometer
Starts with OR21 words
orogeny
oropharynx
orrisroot
orogenesis
oroblanco
orotundity
orthopyroxene
oropendola
orogen
orthopteroid
orthros
orthodromy
orthopteron
orologist
orontium
orographer
orthopterologist
orthonitroaniline
orthrosanthus
ornithocoprolite
orometer
Starts with OS10 words
osteonecrosis
osteoarthrosis
osteopetrosis
osteoarthropathy
osteochondropathy
osteochondrophyte
osteochondrosarcoma
ostrowskia
osteoenchondroma
osteochondrofibroma
Starts with OT
1 words
otosclerotic
Starts with OU15 words
outro
outgrowth
outcrop
outcropping
outgroup
ouroboros
outcross
outcrossing
outstroke
outcrowd
outthrow
outrope
outroper
outroop
outrooper
Starts with OV18 words
overthrow
overground
overgrowth
overproduction
overproof
overgenerosity
overtrousers
overarousal
overcrop
overoptimist
overorganization
overthrower
overpronunciation
overprocrastination
overobjectification
overornamentation
overproportion
overornamentality
Starts with OX
2 words
oxymoron
oxytrope

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