Forming Plural Nouns in English
Rules for Plural Nouns Reference Sheet
Regular Plural Nouns
The plural morphological suffix for most English nouns is simply -s, which is added to
the end of the singular form:
Singular – Plural
apple – apples
brother – brothers
elbow – elbows
holiday – holidays
kite – kites
notebook – notebooks
toe – toes
zebra – zebras
However, if the singular form of the noun ends with s(e) or c(e) [s], z(e) [z], sh [š], ch [č],
or dg(e) [ĵ], then the plural morphological suffix is -es:
Singular – Plural
ash – ashes
box – boxes
church – churches
English – Englishes
judge – judges
kiss – kisses
language – languages
watch – watches
If the singular form of the noun ends with a consonant followed by a y, then the y
changes to an i and is followed by the plural morphological suffix is -es:
Singular – Plural
authority – authorities
body – bodies
cherry – cherries
family – families
history – histories
memory – memories
panty – panties
story – stories
Rules for Plural Nouns Reference Sheet 2
If the singular form of the noun ends with f or fe, then the f or fe changes to a ve and is
followed by the plural morphological suffix is -s:
Singular – Plural
calf – calves
knife – knives
leaf – leaves
life – lives
self – selves
thief – thieves
wife – wives
wolf – wolves
The f or fe to ve rule does not apply if the verb form of the noun ends in ve as in beliefbeliefs (noun) and believe-believes (verb).
Nouns Ending in -o
The plural morphological suffix for English nouns ending in -o is either -s or -es, which
is added to the end of the singular form, depending on the specific noun. If the singular
form of the noun ends with an o preceded by another vowel or vowel sound, then the
plural morphological suffix is -s:
Singular – Plural
bamboo – bamboos
cameo – cameos
duo – duos
embryo – embryos
radio – radios
scenario – scenarios
stereo – stereos
studio – studios
If the singular form of the noun ends in o and the word is of foreign origin including most
musical terms, then the plural morphological suffix is also -s:
Singular – Plural
alto – altos
canto – cantos
kimono – kimonos
photo – photos
piano – pianos
rondo – rondos
solo – solos
taco – tacos
Rules for Plural Nouns Reference Sheet 3
If the singular form of the noun ends with an o preceded by a consonant, then the plural
morphological suffix is -es:
Singular – Plural
domino – dominoes
echo – echoes
embargo – embargoes
hero – heroes
mosquito – mosquitoes
potato – potatoes
tomato – tomatoes
veto – vetoes
For some nouns ending in an o preceded by a consonant, however, the plural
morphological suffix is either -s or -es:
Singular – Plural
avocado – avocados/avocadoes
buffalo – buffalos/buffaloes
desperado – desperados/desperadoes
ghetto – ghettos/ghettoes
halo – halos/haloes
hobo – hobos/hoboes
portico – porticos/porticoes
tornado – tornados/tornadoes
The current trend for spelling the plurals of nouns ending in o preceded by a consonant
seems to be moving in the direction of adding only the morphological suffix -s,
particularly in the case of nouns with variable spellings.
Irregular Plural English Nouns
Unlike regular English nouns for which the plural morphological suffix is either -s or -es,
irregular English nouns require vowel changes, consonant changes, or suffixation. For
some common English nouns of Old English origin, the vowel undergoes an ablaut or
vowel sound change:
Singular – Plural
foot – feet
louse – lice
man – men
mouse – mice
person – people (also consonant sound change)
tooth – teeth
woman – women
Rules for Plural Nouns Reference Sheet 4
For some other common English nouns of Old English origin, the plural morphological
suffix is -en or -n:
Singular – Plural
brother – brethren/brothers (archaic)
child – children
cow – kine/cows (archaic)
eye – eyen/eyes (dialectal)
ox – oxen
hose – hosen/hoses (archaic)
house – housen/houses (dialectal)
shoe – shoon/shoes (dialectal)
For other common English nouns often of Old English origin and referring to groups of
animals, the plural form is identical to the singular form:
Singular – Plural
bison – bison
deer – deer
moose – moose
offspring – offspring
salmon – salmon
sheep – sheep
species – species
trout – trout
Irregular Plural Foreign Nouns
Unlike the plural forms of nouns of English origin, the plurals of nouns borrowed as
loanwords from foreign languages often conserve the plural form from the original
language. If the noun is of Latin origin and ends in a, change the a to an ae:
Singular – Plural
alumna – alumnae
formula – formula
If the noun is of Latin origin and ends in ex or ix, change the ex or ix to ices:
Singular – Plural
index – indices
matrix – matrices
vertex – vertices
Rules for Plural Nouns Reference Sheet 5
If the noun is of Latin origin and ends in is, change the is to an es:
analysis – analyses
axis – axes
crisis – crises
testis – testes
thesis – theses
If the noun is of Latin origin and ends in on, change the on to an a:
automaton – automata
criterion – criteria
phenomenon – phenomena
If the noun is of Latin origin and ends in um, change the um to an a:
addendum – addenda
datum – data
medium – media
memorandum – memoranda
millennium – millennia
If the noun is of Latin origin and ends in us, change the us to an i, era, ora, or es:
alumnus – alumni
cactus - cacti
corpus – corpora
census – censuses
focus – foci
fungus – fungi
genus – genera
radius – radii
syllabus – syllabi
uterus – uteri
viscus – viscera
If the noun is of Greek origin and ends in ma, add the suffix -ta to the end of the word:
dogma – dogmata
schema – schemata
stigma – stigmata
stoma – stomata
Rules for Plural Nouns Reference Sheet 6
If the noun is of French origin and ends in eau, add a silent -x suffix to the end of the
word:
beau – beaux
bureau – bureaux
château – châteaux
If the noun is of Hebrew origin, add the suffix -im or -ot to the end of the word:
cherub – cherubim
matzah – matzot
seraph – seraphim
Like with regular English nouns ending in o, the current trend for spelling the
pronouncing the plurals of loanwords from foreign languages seems to be moving in the
direction of adding only the morphological suffix -s, particularly in the case of
uncommon or infrequent nouns.