Countable Nouns Ending in UM and Containing O
This list gathers 586 English countable nouns ending in UM and containing O, such as Forum, Momentum, Consortium, Podium, Optimum, Auditorium and Continuum. 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 A
24 words auditorium
arboretum
aconitum
abomasum
androecium
archegonium
apodyterium
aeonium
allodium
appressorium
aspersorium
amomum
acroterium
anthodium
apothecium
anhalonium
aeroperitoneum
androconium
anticlinorium
androsporangium
archesporium
androphorum
aeciotelium
androgonium
Starts with B
17 words botulinum
boojum
bonum
bulbophyllum
bronchium
brontotherium
bryophyllum
brosimum
botrychium
bothrium
bulbocodium
benzenediazonium
bromatium
brimborium
botrydium
brontozoum
bronteum
Starts with C
24 words consortium
continuum
condominium
conundrum
colosseum
coliseum
compendium
colloquium
crematorium
corundum
columbarium
clostridium
cryptosporidium
collegium
corium
corrigendum
cyanobacterium
conservatorium
ciborium
collum
callosum
coagulum
conium
colchicum
Starts with D
22 words decorum
duodenum
dolphinarium
dorsum
demonstrandum
depositum
dendrobium
diazonium
deinotherium
desmodium
domatium
doum
diphyllobothrium
denotatum
dockominium
dolium
digitorium
doronicum
diaconicum
dinotherium
dracocephalum
deutovum
Starts with E
24 words emporium
endometrium
euphonium
endothelium
encomium
endocardium
exordium
eulogium
endomysium
eupatorium
endosteum
endoneurium
enterobacterium
epilobium
eponychium
erythroxylum
etymologicum
excubitorium
elotherium
erythronium
endothecium
ecomuseum
eriogonum
eurotium
Starts with F
10 words forum
factotum
folium
fideicommissum
filopodium
formicarium
florilegium
feodum
fumatorium
falcatifolium
Starts with G
8 words gynoecium
gymnatorium
gymnocalycium
glochidium
gonium
gonidium
gynostemium
graptopetalum
Starts with H
21 words hoodlum
honorarium
harmonium
hospitium
hordeolum
hypochondrium
hydronium
hypogeum
heliotropium
haustorium
hypogastrium
horologium
helminthosporium
hydropericardium
hyracotherium
hylotelephium
hydroxonium
hematopericardium
hymenosporum
hormogonium
hydropneumopericardium
Starts with I
10 words inoculum
indecorum
ignotum
idolum
involucrum
infusorium
involucellum
ichthyopterygium
inclinatorium
inhalatorium
Starts with J
1 words jorum
Starts with K
3 words kokum
kookum
khoum
Starts with L
20 words linoleum
locum
lycopodium
loropetalum
leprosarium
lamellipodium
leontopodium
limonium
leptospermum
lithospermum
lolium
leucospermum
lobopodium
latrocinium
leucojum
leucophyllum
laconicum
lubritorium
lomentum
lygodium
Starts with M
24 words momentum
memorandum
moratorium
mausoleum
modicum
myocardium
myometrium
molluscum
mycobacterium
mesothelium
muonium
microsporangium
megasporangium
mesogastrium
melampodium
monopodium
macrosporangium
mortarium
maggotorium
monochasium
motorium
macrophylum
myosotidium
metapostscutellum
Starts with N
14 words nostrum
natatorium
novum
nonpetroleum
neuroepithelium
nanobacterium
notandum
nitronium
notum
nitrobacterium
notaeum
nitrosobacterium
nototherium
nipponanthemum
Starts with O
24 words optimum
opossum
ovum
omnium
omentum
organum
ostium
odeum
operculum
omasum
oceanarium
onium
origanum
oppidum
oogonium
ommatidium
oncidium
osculum
opusculum
oidium
ornithogalum
osmiridium
ostensorium
orarium
Starts with P
24 words podium
possum
pandemonium
proscenium
peritoneum
plasmodium
poppadum
primordium
praetorium
positronium
pelargonium
periosteum
pantoum
pittosporum
pomatum
propionibacterium
prothalamium
precordium
pseudopodium
procambium
pronotum
perichondrium
phosphonium
pomerium
Starts with Q
2 words quorum
quotum
Starts with R
9 words rostrum
rhizobium
responsum
radiostrontium
rosarium
rostellum
rhodanthemum
rhynchosporium
respiratorium
Starts with S
24 words symposium
scrotum
sorghum
sanatorium
solarium
subforum
sporangium
solanum
scriptorium
solum
suboptimum
sensorium
solatium
syngonium
skookum
stramonium
scholium
spermatogonium
soum
sclerotium
scolopendrium
sourgum
stomium
stomodeum
Starts with T
18 words tentorium
tropaeolum
teetotum
triforium
trifolium
tetrazolium
tormentum
taurobolium
tomentum
tetramethylammonium
tomium
trachelospermum
tripleurospermum
tirocinium
tridominium
tritocerebrum
tetrasporangium
trichosporangium
Starts with U
1 words uropygium
Starts with V
5 words vomitorium
variorum
veronicastrum
verumontanum
vivisectorium
Starts with X
6 words xiphosternum
xenodochium
xerophyllum
xenophyum
xeromyrum
xylomelum
Starts with Z
14 words zanthoxylum
zygopetalum
zoosporangium
zygosporangium
zooecium
zygophyllum
zoarium
zygomaticum
zoospermium
zoogonidium
zoothecium
zoocecidium
zoocytium
zoodendrium