Singular and Plural Nouns in English

*) Basic Rule: Add –s

The basic rule for forming plurals is to add -s to the noun. Below are some examples:

cat → cats
book → books
car → cars
dog → dogs
apple → apples
banana → bananas
orange → oranges
bird → birds
present → presents
animal → animals
pencil → pencils
plate → plates

*) Add –es for Nouns Ending in s, x, z, ch, sh

Use –es for words ending in s, x, z, ch, sh

bus → buses
box → boxes
quiz → quizzes (requires doubling the "z")
church → churches
dish → dishes
fox → foxes
match → matches
lunch → lunches
peach → peaches
watch → watches
wish → wishes
brush → brushes

*) Irregular Plurals: No Clear Pattern

Some plural forms are irregular; they are called irregular plurals. Below are some examples:

man → men
woman → women
child → children
person → people
foot → feet
tooth → teeth
goose → geese
mouse → mice
ox → oxen
crisis → crises
thesis → theses
criterion → criteria
phenomenon → phenomena
stimulus → stimuli
cactus → cacti
focus → foci
nucleus → nuclei
fungus → fungi
syllabus → syllabi
alumnus → alumni
octopus → octopi
louse → lice
datum → data
curriculum → curricula
appendix → appendices

*) Change –f or –fe to –ves

For nouns ending in –f or –fe, change –f or –fe to –ves:

knife → knives
leaf → leaves
life → lives
loaf → loaves
thief → thieves
scarf → scarves
shelf → shelves
wife → wives
calf → calves
elf → elves
half → halves
self → selves

Exception： Not all nouns that ending in -f change to —ves, some just add –s.

chief → chiefs
roof → roofs
belief → beliefs
chef → chefs
cliff → cliffs

3. Nouns Ending in -o

Add –es for Nouns Ending in Consonant + o

tomato → tomatoes
potato → potatoes
hero → heroes
echo → echoes
torpedo → torpedoes
tornado → tornadoes
domino → dominoes

mango → mangoes / mangos *
cargo → cargoes / cargos *
mosquito → mosquitoes / mosquitos *
volcano → volcanoes / volcanos *
buffalo → buffaloes / buffalos *

* Adding -es is more common. But adding –s is considered acceptable too.

Add –s for Nouns Ending in Vowel + o

zoo → zoos
radio → radios
studio → studios
video → videos
kangaroo → kangaroos
portfolio → portfolios
bamboo → bamboos

Exception: Nouns Ending in Consonant + “o” That Take –s, Not –es:

While many nouns ending in a consonant + “o” take –es, there are notable exceptions that simply add –s:

piano → pianos
photo → photos
memo → memos
casino → casinos
piccolo → piccolos

Some nouns accept either –s or –es as plural. Both are grammatically correct, but –s is more common and widely accepted in modern usage.

zero * → zeros / zeroes
* "zeros" is more common and widely accepted.
avocado * → avocados / avocadoes
* "avocados" is more common and widely accepted.

4. Nouns Ending in –y

If a noun ends in a consonant + y, change y to ies:

baby → babies
city → cities
story → stories
country → countries

spy → spies
army → armies
puppy → puppies
butterfly → butterflies
cherry → cherries

But if the noun ends in a vowel + y, just add –s:

toy → toys
key → keys
boy → boys
day → days
birthday → birthdays
monkey → monkeys
guy → guys

7. Unchanging Plural Nouns (also called Invariable Nouns)

Some nouns have the same form whether singular or plural. No need to add -s or -es, even when you're talking about many.

aircraft → aircraft

So whether you're talking about one jet or an entire fleet, you just say aircraft. No "s", no "es".

🛩 Singular & Plural Use of Aircraft

✈️ Singular Use

“The aircraft landed safely despite the heavy fog.”
“That aircraft can reach speeds of Mach 2.”

🛬 Plural Use (Same Form)

“Several military aircraft were deployed to the region.”
“The airport handles over 500 aircraft every day.”

Grammar Tip: Aircraft is an invariable noun, meaning its form stays the same for both singular and plural. No need to add –s or –es.

Other nouns like this include:

sheep → sheep
deer → deer
salmon → salmon
tuna → tuna
fish → fish

species → species
series → series
trout → trout
moose → moose
bison → bison
swine → swine
cod → cod
reindeer → reindeer
offspring → offspring
headquarters → headquarters

📘 Singular & Plural Use of Fish

🎣 Singular Use

“I caught one fish.”

🐠 Plural Use (Same Form)

“We saw ten fish in the pond.”

🌍 Plural Species Use

“The aquarium contains fishes from the Amazon, the Pacific, and the Atlantic.”

Grammar Tip: The word fish is both singular and plural when referring to quantity. But fishes is used to describe multiple species.

8. Plural-Only Noun

A plural-only noun refers to a noun that exists only in its plural form.

They all refer to things that are essentially one item, but made of two parts—so the plural form is the default.

These nouns don’t have a singular version, even when referring to just one item or concept.

👖 trousers
👖 jeans
🩳 shorts
✂️ scissors
👓 glasses