Countable Nouns

Nouns may be both singular and plural. A singular noun refers to nouns where we talk of one of them, these are typically followed by “a” or “one”, to denote this.

Plural nouns are therefore nouns where we are referring to more than one of them. These are typically followed by “two”, “three”, “seven”, or any other number, and by words such as “much” or “many”. Singular and plural nouns may be further divided into two categories, namely; regular and irregular.

Regular Plural Nouns

Singular and plural nouns generally follow the convention of using an -s. For example, take the noun “cat”. In singular form we refer to only a single instance of the noun:

a cat

one cat

However in the plural form we are referring to more than one cat, thus:

two cats

three cats

many cats

lots of cats

tons of cats

The rule of -s is the most common way of making a noun plural and requires nothing more than simply adding an -s to the end of the noun. There are however a few exceptions, which are categorised as an irregular form.

Irregular Plural Nouns

When the plural form of a noun requires more than simply adding an -s to the end of it, we call it an irregular form. There are several of these irregular forms:

Nouns ending in -y

Take the nouns “monkey” and “baby”, for example. Nouns that end in a -y do so by either following a vowel or a consonant, as is the case in “monkey” and “baby” respectively. If the letter that the -y follows is a vowel, then we simply use the rule of -s like is shown previously, thus: “monkeys”.

However, in the case of nouns where the letter that the -y follows is a consonant, we transform the -y into an -ie and then add an -s:

baby	babies
monkey	monkies
lady	ladies

Nouns ending in -s, -ss, -x, -ch, -sh

Consider the nouns “bus”, “glass”, “fox”, “beach”, “brush”. In each of these cases, we make the noun plural by adding an -es to the end of the word. It follows that:

bus	buses
glass	glasses
fox	foxes
beach	beaches
brush	brushes

Exception — Some nouns ending in -us

A significant portion of the words in the English language has roots in Latin. In the case of several nouns that have a Latin root and end with -us, they are made plural by replacing the -us with an -i. Take care to note that in these nouns the -i is pronounced as if it were a stand-alone “I”.

Consider the nouns “focus”, “radius”, “fungus”, “nucleus”, “cactus” and “alumnus”:

focus	foci
radius	radii
fungus	fungi
nucleus	nuclei
cactus	cacti
alumnus	alumni

Exception — Some nouns ending in -is

Nouns ending in -is are made plural by replacing the -is with an -es. This is the case for nouns such as “axis”, “basis”, “crisis” and “oasis”:

axis	axes
basis	bases
crisis	crises
oasis	oases

Exception — Some nouns ending in -z and -s

Nouns that end with a -z are a constant source of confusion for those learning English when determining their plural form. There are further exceptions to the following rule, however in most cases, these nouns are made plural by adding an additional -z and then an -es. Thus, for nouns such as “quiz” and “shiraz”:

quiz	quizzes
shiraz	shirazzes

There are also instances of nouns that end in an -s that are made plural by adding an additional -s and then an -es. For example, the plural form of “gas” is “gasses” but is often accepted and given as “gases”.

Nouns ending in -fe

Nouns that end in -fe are made plural by changing the -fe to a -ve and then adding an -s. Examples of these are nouns such as “life”, “wife” and “knife”:

life	lives
wife	wives
knife	knives

Nouns ending in -f

Most Nouns that end in an -fe are made plural by using the rule of -s. However, there are several exceptions that are made plural similarly to those ending with an -fe. That is by changing the f to a -ve and then adding an -s.

Examples of these are nouns such as “half”, “leaf”, “wolf” and “calf”:

half	halves
leaf	leaves
wolf	wolves
calf	calves

Nouns ending in -o

Many nouns that end in -o are made plural by simply using the rule of -s. This is especially true for the case where the letter that precedes the -o is a vowel. There are however several nouns that end in an “o” that are made plural by adding an “es”, similarly to nouns ending in -s, -ss, -x, -ch or -sh.

Consider the words: “echo”, “hero”, “potato”, “tomato” and “buffalo”:

echo	echoes
hero	heroes
potato	potatoes
tomato	tomatoes

There are instances where a noun ending in an -o may be made plural by either adding an -s or an -es. For example:

buffalo

buffalos

buffaloes

Nouns ending in -on

A select few nouns that end with an -on are made plural by replacing the -on with an -a. This occurs in words such as “phenomenon” and “criterion”:

phenomenon	phenomena
criterion	criteria

It is however worth noting that many nouns that end in -on are made plural simply by using the rule of -s.

Nouns where the entire word is changed

Many nouns are made plural by being entirely replaced by a new noun that is entirely dedicated to indicating the plural of the noun. There are some similarities between these words, but there are unfortunately no rules. They simply must be memorized. Some of these nouns are “man”, “foot”, “child”, “person”, “tooth” and “mouse”:

man	men
foot	feet
child	children
person	people
tooth	teeth
mouse	mice

Nouns that are unchanged in their plural form

A selection of nouns remains the same in their singular and plural forms. Some of these unchanged nouns are “sheep”, “deer” and “fish”:

sheep

deer

fish