English Grammar, Third edition (2011)
Reference Section
Forming plurals of countable nouns
R2 Information on which nouns have plurals is given in Chapter 1 (1.14 to 1.193).
R3 In most cases, the plural is written s.
hat |
hats |
|
tree |
trees |
R4 The plural is written es after sh, ss, x, or s, and it is pronounced /Iz/.
bush |
bushes |
|
glass |
glasses |
|
box |
boxes |
|
bus |
buses |
The plural is also written es and pronounced /Iz/ after ch, when the ch is pronounced /tʃ/.
church |
churches |
|
match |
matches |
|
speech |
speeches |
R5 When the s follows one of the sounds /f/, /k/, /p/, /t/, or /θ/, it is pronounced /s/.
belief |
beliefs |
|
week |
weeks |
|
cap |
caps |
|
pet |
pets |
|
moth |
moths |
R6 When the s follows one of the sounds /S/, /z/, or /ʤ/, it is pronounced /IΖ/.
service |
services |
|
prize |
prizes |
|
age |
ages |
R7 Some nouns that end with the sound /θ/, for example mouth, have their plural forms pronounced as ending in /ðΖ/. With others, such as bath and path, the pronunciation can be either /θs/ or /ðΖ/. You may need to check the pronunciations of words like these in a Cobuild dictionary.
R8 In most other cases the s is pronounced /z/.
bottle |
bottles |
|
degree |
degrees |
|
doctor |
doctors |
|
idea |
ideas |
|
leg |
legs |
|
system |
systems |
|
tab |
tabs |
R9 With nouns that end in a consonant letter followed by y, you substitute ies for y to form the plural.
country |
countries |
|
lady |
ladies |
|
opportunity |
opportunities |
With nouns that end in a vowel letter followed by y, you just add s to form the plural.
boy |
boys |
|
day |
days |
|
valley |
valleys |
R10 There are a few nouns ending in f or fe where you form the plural by substituting ves for f or fe.
calf |
calves |
|
elf |
elves |
|
half |
halves |
|
knife |
knives |
|
leaf |
leaves |
|
life |
lives |
|
loaf |
loaves |
|
scarf |
scarves |
|
sheaf |
sheaves |
|
shelf |
shelves |
|
thief |
thieves |
|
wife |
wives |
|
wolf |
wolves |
R11 With many nouns that end in o, you just add s to form the plural.
photo |
photos |
|
radio |
radios |
However, the following nouns ending in o have plurals ending in oes :
domino
echo
embargo
hero
negro
potato
tomato
veto
The following nouns ending in o have plurals that can end in either s or es:
buffalo
cargo
flamingo
fresco
ghetto
innuendo
mango
manifesto
memento
mosquito
motto
salvo
stiletto
tornado
torpedo
volcano
R12 The following nouns in English have special plural forms, usually with different vowel sounds from their singular forms:
child |
children |
|
foot |
feet |
|
goose |
geese |
|
louse |
lice |
|
man |
men |
|
mouse |
mice |
|
ox |
oxen |
|
tooth |
teeth |
|
woman |
women |
R13 Most nouns that refer to people and that end with man, woman, or child have plural forms ending with men, women, or children.
postman |
postmen |
|
Englishwoman |
Englishwomen |
|
grandchild |
grandchildren |
R14 In addition to the nouns mentioned above, there are words that are borrowed from other languages, especially Latin, and that still form their plurals according to the rules of those languages. Many of them are technical or formal, and some of those that are given below are also used with a regular s or es plural ending in non-technical or informal contexts. You may need to check these in a Cobuild dictionary.
R15 Some nouns ending in us have plurals ending in i.
cactus |
cacti |
|
focus |
foci |
|
nucleus |
nuclei |
|
radius |
radi |
|
stimulus |
stimuli |
R16 Some nouns ending in um have plurals ending in a.
aquarium |
aquaria |
|
memorandum |
memoranda |
|
referendum |
referenda |
|
spectrum |
spectra |
|
stratum |
strata |
R17 Most nouns ending in is have plurals in which the is is replaced by es.
analysis |
analyses |
|
axis |
axes |
|
basis |
bases |
|
crisis |
crises |
|
diagnosis |
diagnoses |
|
hypothesis |
hypotheses |
|
neurosis |
neuroses |
|
parenthesis |
parentheses |
R18 With some nouns ending in a, the plurals are formed by adding e.
larva |
larvae |
|
vertebra |
vertebrae |
Some, such as antenna, formula, amoeba, and nebula, also have less formal plurals ending in s.
R19 Other nouns form their plurals in other ways. Some of these have two plural forms, one formed with s and one formed in a different way. Usually the form with s is used in less formal English.
appendix |
appendices or appendixes |
|
automaton |
automata or automatons |
|
corpus |
corpora or corpuses |
|
criterion |
criteria |
|
genus |
genera |
|
index |
indices or indexes |
|
matrix |
matrices |
|
phenomenon |
phenomena |
|
tempo |
tempi or tempos |
|
virtuoso |
virtuosi or virtuosos |
|
vortex |
vortices |