Plural nouns

###What does it mean to make a noun plural?

You form a plural noun when you add an ending or change the noun to show that there is more than one of it.

Example: one child, several children

###Forming regular plural nouns

Regular plural nouns follow predictable rules when you change them from singular (one) to plural (more than one). To create regular plural nouns, you just add -s, -es, or -ies to the end of the word.

Rule | Singular | Plural

• | - | -
  Add -s to most nouns. | experiment | experiments
  Add -es to nouns ending in s, x, z, ch, or sh. | fox | foxes
  When y follows a consonant, change y to i and add -es. | policy | policies
  When y follows a vowel, add -s. | essay | essays
  When o follows a vowel, add -s. | video | videos
  When o follows a consonant, add -s or -es, depending on the word. | volcano | volcanoes

###Forming irregular plural nouns

Irregular plural nouns don't follow the same rules. You have to memorize these special plurals because the nouns change in unexpected ways or don't change at all. Here are a few of the most common types of irregular plural nouns:

####Plural nouns formed by changing f or fe to ves

Singular | Plural

• | -
  knife | knives
  half | halves
  leaf | leaves
  loaf | loaves
  thief | thieves

Note that many nouns that end in f or fe don't follow this pattern! For example, the plural of roof is roofs and the plural of chief is chiefs.

####Plural nouns formed by adding en to the end of a word

Only two common nouns in English follow this pattern.

Singular | Plural

• | -
  child | children
  ox | oxen

In historical or religious texts, you may also see brethren, a plural form of brother.

####Plural nouns formed by changing a vowel sound

Only seven words in English follow this pattern.

Singular | Plural

• | -
  tooth | teeth
  goose | geese
  foot | feet
  woman | women
  man | men
  mouse | mice
  louse | lice

####Plural nouns that are the same as the singular form

These are called "base plurals" or "zero plurals."

Singular | Plural

• | -
  sheep | sheep
  deer | deer
  moose | moose
  trout | trout
  salmon | salmon
  aircraft | aircraft
  spacecraft | spacecraft
  offspring | offspring
  species | species
  series | series

[[☃ explanation 1]]

####Plural nouns formed by changing us to i

Singular | Plural

• | -
  cactus | cacti
  fungus | fungi
  stimulus | stimuli
  nucleus | nuclei
  focus | foci
  radius | radii

Some English words come from Latin. For these Latin words, when the singular form ends in us, the plural is formed by changing us to i.

Be careful though! Not every word that ends in us follows this pattern. For example, the plural of octopus is octopuses, not octopi, because the word octopus comes from Greek, not Latin.

For more information on pluralizing English words from foreign languages, check out this video.

###Remember!

Regular plurals follow patterns you can learn, like adding s or es. Irregular plurals break the rules and must be memorized.