English Plural Nouns

How to Form Regular Plural Nouns

The most common way to form the plural of a noun in English is by adding -s to the end of the word. This rule applies to most nouns. For example:

• book → books

• car → cars

• table → tables

• dog → dogs

However, if the noun ends in -s, -ss, -sh, -ch, -x, or -z, the plural is formed by adding -es. For example:

• bus → buses

• glass → glasses

• lunch → lunches

• box → boxes

For nouns ending in -o, the plural is usually formed by adding -es. For example:

• tomato → tomatoes

• mosquito → mosquitoes

• hero → heroes

• echo → echoes

But there are exceptions where only -s is added:

• piano → pianos

• photo → photos

• kilo → kilos

• video → videos

For nouns that end in a consonant followed by -y, the -y is usually changed to -ies to form the plural. For example:

• city → cities

• baby → babies

• story → stories

• party → parties

If the noun ends in a vowel followed by -y, simply add -s:

• boy → boys

• day → days

• key → keys

• journey → journeys

For most words ending in -f or -fe, we change the -f to a -v and then add -es:

• leaf → leaves

• half → halves

• wife → wives

• life → lives

However, there are some exceptions where the -f doesn’t change and only -s is added:

• roof → roofs

• belief → beliefs

• chef → chefs

• cliff → cliffs

If the noun ends in -us, the plural ending is often -i:

• cactus → cacti

• focus → foci

• alumnus → alumni

• radius → radii

If the singular noun ends in -is, the plural ending is -es:

• thesis → theses

• crisis → crises

• diagnosis → diagnoses

• analysis → analyses

Irregular Plural Nouns

English has many nouns that don’t follow the regular pluralization rules. These irregular plurals must be memorized, as there are no specific rules to follow. Here are some common examples:

• child → children

• man → men

• woman → women

• person → people

• foot → feet

• tooth → teeth

• mouse → mice

Some nouns retain their original form when pluralized. That is, the singular and plural form of the word are the same. For example:

• sheep (one sheep, two sheep)

• fish (one fish, two fish) – though fishes is also acceptable in certain contexts

• series (one series, two series)

• species (ones species, two species)