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When creating a piece of writing, there are many rules to follow to ensure your spelling and grammar remain correct. Spellings can provide lots of places for us to trip up - especially when it comes to plurals. Not to worry, though! In this article, we'll have a look at different aspects of plurals, including:

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When creating a piece of writing, there are many rules to follow to ensure your spelling and grammar remain correct. Spellings can provide lots of places for us to trip up - especially when it comes to plurals. Not to worry, though! In this article, we'll have a look at different aspects of plurals, including:

  • The meaning of plural

  • Types of plurals

  • Regular plural nouns

  • Irregular plural nouns

  • The rules for regular and irregular plural nouns

  • Examples of plurals

Plurals Meaning

Before we begin discussing plurals, let's make sure we know what plural means.

If something is plural, it means there is more than one of it. Only nouns, pronouns, or determiners can be either singular or plural.

Nouns are initially considered in their singular form and are modified to become plurals. This process is referred to as pluralization. The pluralization process most commonly involves adding suffixes (e.g., -s); however, the process can differ between different types of nouns.

Pronouns and determiners each have their own sets of words that denote pluralization:

  • Pronouns = we, you, and they

  • Determiners = these and those

In this article, we will focus on the plural forms of nouns.

Plural Nouns

Now we have a good idea of the meaning of the term plural, let's refresh ourselves with what a noun is.

A noun is a part of speech used to name a person, place, object, or concept.

Here are some examples of singular and plural nouns. Familiarize yourself with these before we go on to discuss them in more detail.

  • box - boxes
  • splash - splashes
  • reindeer - reindeer
  • fish - fish/fishes
  • cactus - cacti
  • hobbit - hobbits
  • leaf - leaves
  • cup - cups
  • gas - gasses
  • roof - roofs
  • guppy - guppies
  • tomato - tomatoes

You might notice that some of these words have been pluralized in different ways. This is because they are different types of plural nouns (e.g., regular, irregular, or zero) and therefore follow different rules to create plural forms.

Fish or Fishes?

People often get confused with the plural form of fish, but the rule is quite simple.

When there are multiple fish of the same breed, the plural is fish.

When there are multiple different breeds of fish, the plural is fishes.

Types of Plural Nouns

So, what are the different types of plural nouns?

There are three types of plural nouns:

  • Regular plural nouns

  • Irregular plural nouns

  • Zero plural nouns (nouns that don't change when pluralized)

We'll now discuss each of these in turn.

Regular Plural Nouns

Regular plural nouns are nouns in which we add the affix '-s' to the end of the singular form to create the plural.

Inflectional Affixes

An inflectional affix is a letter or group of letters added to a root word to show a grammatical change. When a word undergoes an inflectional change, the core meaning of the word stays the same.

Inflections can show a change in:

  • Number, e.g., + '-s'
  • Aspect, e.g., + '-ing'
  • Person, e.g., + '-s'
  • Tense, e.g., + '-ed'

Some examples of regular plural nouns are shown below:


Plurals Image of dogs StudySmarterFig. 1 - Dogs is a regular plural noun - meaning the affix '-s' is added to the end.

Irregular Plural Nouns

Irregular plural nouns are nouns that don't follow the regular rule of adding an '-s'. There are many different rules for creating irregular plurals, each depending on what letters the singular word ends in. Let's look at some of the most important rules now.

Rules for Irregular Plural Nouns

Most of the rules for irregular plural nouns depend on the ending letters of the noun. For example, a word ending with 'ch' follows a different rule than a word ending with 'f'.

Words that End in 'S', 'SS', 'SH', 'CH', 'X', or 'Z'

These words are the closest to following the regular add an '-s' rule of regular plurals. However, for these words, you need to add '-es' to make them plural.

Some examples of words like these are:

bus buses

moss → mosses

wish wishes

beach beaches

box boxes

blitz blitzes

There is a slight exception to this rule. Some words that end in a single -s (such as gas), add another 's' before the '-es', e.g., gasses.

Words that End in 'F' or 'FE'

Most of the words that end in '-f' or '-fe' change to '-ve' before the plural '-s' is added. Here are some examples:

calf calves

knife knives

leaf leaves

wife wives

life lives

loaf loaves

Not all words ending in '-f' follow this rule, however, and words that end in '-ff' (e.g., puff or huff) usually follow the rule of regular plurals and just have an '-s' added (e.g. puffs or huffs). Additionally, some words ending in a singular '-f' simply use the regular plural rule (roof roofs).

Words that End in 'Y'

Words that end in '-y' can be split into two types.

  • Words with a '-y' following a consonant (e.g., city)

  • Words with a '-y' following a vowel (e.g., toy)

The latter type follows the same rule for regular plurals, meaning you just need to add an '-s' to make it plural (e.g., toys).

The first type discussed are irregular plurals and follow a consistent rule: remove the '-y' and replace it with '-ies'. Let's have a look at some examples:

puppy puppies

lorry lorries

activity activities

baby babies

berry berries

spy spies

Words that End in 'O'

Words ending with '-o' can follow both regular and irregular plural rules, ending either in '-s' or '-es'. Unfortunately, there are no set rules to which words end with which affix, and they simply need to be learned.

Let's have a look at some irregular forms:

potato potatoes

tomato tomatoes

hero heroes

echo echoes

And some regular forms:

  • photo photos

  • piano pianos

  • logo logos

To add to the confusion, some words ending in '-o' can be pluralized in either the regular or irregular form. Here's a list of some of the words that can take either form:

  • volcano volcanos or volcanoes

  • tornado tornados or tornadoes

  • mosquito mosquitos or mosquitoes

  • buffalo buffalos or buffaloes

Plurals Image of volcano StudySmarterFig. 2 - The plural of volcano can be volcanos or volcanoes.

Words that End in 'UM'

For words that end with '-um' the plural form is most often created by removing the '-um' and replacing it with an '-a'. For example:

datum data

millennium millennia

spectrum spectra

Some words that end in '-um' can also be pluralized by adding an '-s' to the end. For example, the word forum can be pluralized to either fora or forums (this being the more common plural form).

Words that End in 'ON'

When singular nouns ending with '-on' are pluralized, the '-on' is usually replaced with an '-a'. This can be seen in the following examples:

phenomenon phenomena

automaton automata

criterion criteria

Words that End in 'IS'

Words ending with '-is' and '-es' are often easily confused (e.g., analysis and analyses), but there's a simple rule to follow to help you understand the difference/

The singular form of a word ends in '-is,' and the plural forms end in '-es.' You can see this in the following words:

crisis crises

analysis analyses

axis axes

nemesis nemeses

Words that End in 'US'

Singular nouns that end in '-us' are often pluralized by replacing the ending with an '-i.' Let's have a look at some examples:

cactus cacti

radius radii

alumnus alumni

fungus fungi

There are exceptions to this rule, and some singular nouns ending in '-us' are instead altered to end in '-era,' '-ora,' or '-es.' Here are some examples of where this occurs:

genus genera

corpus corpora

octopus octopuses

Words the End in 'EX' or 'IX'

The final rule for pluralizing irregular nouns applies to words that end in either '-ex' or '-ix.' In these cases, the endings are replaced with '-ices' to create a plural. Here are some words that have these endings:

vertex vertices

index indices

appendix appendices

Zero Plural Nouns

Now that we've looked at all of the rules for irregular plural nouns, let's look at nouns that have the same spelling for both their singular and plural forms - zero plural nouns.

There isn't a rule for identifying these irregular plurals; you simply need to memorize them. Don't worry, though, as many of these will be words you've come across before.

  • fish
  • deer
  • reindeer
  • species
  • series
  • sheep

Plurals Image of sheep StudySmarterFig. 3 - The plural of sheep is simply sheep

Nouns that Change Completely for Pluralization

Another type of irregular plural noun is nouns that change their spelling completely from their plural forms. These changes in spellings tend not to follow any rule and also need to be memorized.

Here's a list of nouns that have different spellings in their singular and plural forms:

  • person - people

  • child - children

  • man - men

  • woman - women

  • mouse - mice

  • goose - geese

  • louse - lice

  • ox - oxen

  • foot - feet

  • tooth - teeth

  • penny - pence

Examples of Plurals

Now that we've gone through all of the rules for plural nouns, let's recap them all with an example for each.

RuleSingular FormPlural Form
Regular pluralslaptop, thoughtlaptops, thoughts
Nouns ending with -S, -SS, -SH, -CH, -X, and -Z bus, lass, galosh, witch, fox, fezbuses, lasses, galoshes, witches, foxes, fezzes
Nouns ending with -F or -FE elf, wifeelves, wives
Nouns ending with -Y bunnybunnies
Nouns ending with -Oheroheroes
Nouns ending with -UM datumdata
Nouns ending with -ONcriterioncriteria
Nouns ending with -IS crisiscrises
Nouns ending with -US radiusradii
Nouns ending with -EX or -IXvertex, appendicesvertices, appendices
nouns that stay the samespecies, sheepspecies, sheep
nouns that change almost completelyperson, footpeople, feet

Plurals - Key Takeaways

  • Nouns go through an inflection process to show their plural form. Regular plural nouns have an -S added to the end of the word.
  • Singular nouns that end in -S, -SS, -SH, -CH, -X, or -Z often need -ES added to create their corresponding plural forms.
  • There are different types of irregular plural nouns, each of which follows its own rules to form plurals.
  • Some irregular plural nouns are identical to their singular forms (such as sheep).
  • Some irregular plural nouns don't follow a pattern and their spelling changes entirely (such as person people and tooth teeth).

Frequently Asked Questions about Plurals

Plurals are forms of nouns that refer to more than one. For example, "one dog" uses a singular form dog, while "three dogs" uses the plural form dogs. 

Plurals are forms of words (usually nouns) that refer to multiple items of the nouns being discussed. For example, tables, violinists, corpora and data are all plural forms of nouns.

You can use the term "plural" in a sentence to refer to something that is 'more than one.' "Plural" also describes forms of nouns that refer to more than one of their namesake. 

The singular noun leaf is altered to leaves for its plural form. An example of the plural form in a sentence could be:

The leaves were falling from the trees quickly now that the summer was over.

Plural nouns can be separated into either regular or irregular plurals. Regular plural nouns occur when an -S is added onto the singular form. Irregular plural nouns are divided into different categories depending on the ending letters of the singular form. Each ending has it's own rules regarding pluralization. There are also some plurals that have the same form as their singular counterparts.

Test your knowledge with multiple choice flashcards

What does it mean if something is plural?

Which word group has words that can be converted into plural forms?

Which term is most often used to describe the opposite of plural?


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