Countable Nouns Starting with O and Containing IA

This list gathers 75 English countable nouns starting with O and containing IA, such as Official, Opiate, Obsidian, Optician, Obstetrician, Octogenarian and Onomatopoeia. Use the sorting controls below to organize entries by length, or consult our noun grammar guide to review singular and plural count rules.

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Starts with OB6 words
obsidian
obstetrician
obviation
obviator
obelia
obedientiary
Starts with OC5 words
octogenarian
octennial
ochlophobiac
octandrian
octonarian
Starts with OD
2 words
odontalgia
odontophobia
Starts with OF7 words
official
officiant
officiator
officiality
officiation
officiary
officialty
Starts with OH
1 words
ohia
Starts with OL3 words
olympiad
olearia
olfactophobia
Starts with OM
2 words
omniarch
omnipotentiality
Starts with ON4 words
onomatopoeia
onychia
onomastician
oneirodynia
Starts with OP14 words
opiate
optician
ophidian
ophidiophobia
opuntia
ophthalmoplegia
opisthobranchiate
ophthalmodiagnosis
ophidiarium
ophthalmophobia
opisthocoelian
opsomaniac
ophthalmodiastimeter
ophthalmorrhagia
Starts with OR12 words
orleanian
oratorian
orgia
ornithischian
orgiast
ornithophobia
organomercurial
orchidomaniac
ornithodelphian
orarian
orthodiagonal
orthopsychiatrist
Starts with OS7 words
osteria
ostia
ossia
osmophobia
ostiary
osmiate
ostrowskia
Starts with OT
1 words
otalgia
Starts with OU
2 words
outmarriage
ourisia
Starts with OV8 words
overdiagnosis
overspecialization
overfamiliarity
overcommercialization
overappreciation
overpronunciation
overartificiality
overdenunciation
Starts with OZ
1 words
ozarkian

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