Nouns are a diverse group of words, and they are very common in English. Nouns refer to things—the names of people (Dr. Sanders, lawyers), places (Kansas, factory, home), things (scissors, sheet music, book), or ideas (love, truth, beauty, intelligence).


Icon of two men wearing suitsEnglish has both regular and irregular plural nouns. Regular plurals follow this rule (and other similar rules), but irregular plurals are, well, not regular and don’t follow a “standard” rule.

Regular Plurals

Let’s start with regular plurals: regular plural nouns use established patterns to indicate that there is more than one of a thing. As was mentioned earlier, we add the plural suffix –s or –es to most words (cats, zebras, classes, foxes, heroes). Remember that when words have a foreign origin (e.g., Latin, Greek, Spanish), we just add the plural suffix –s (tacos, avocados, maestros).

When a word ends in y and there is a consonant before y, we change the y to i and add –es. Thus sky becomes skies. However, if the y follows another vowel, you simply add an –s. (donkeysalloys). When a word ends in –f or –fe, we change the f to v and add –es (calvesleaves). However, if there are two terminal fs, or if you still pronounce the f in the plural, you simply add an –s (cliffschiefs).

Irregular Plurals

Irregular plurals, unlike regular plurals, don’t necessarily follow any particular pattern—instead, they follow a lot of different patterns. For this reason, irregular plurals require a lot of memorization. If you’re ever in doubt, the dictionary is there for you.

The first kind of irregular plural we’ll talk about is the no-change or base plural. In these words, the singular noun has the exact same form as the plural (sheepfishdeer, moose). Most no-change plurals are types of animals.

The next type of irregular is the mid-word vowel change. This includes words like toothman, and mouse, which become teethmen, and mice.

Note: The plural for a computer mouse (as opposed to the fuzzy animal) can either be mice or mouses. Some people prefer mouses as it creates some differentiation between the two words.

We also have the plural –en. In these words, –en is used as the plural ending instead of –s or -es.

  • child → children
  • ox → oxen
  • brother → brethren
  • sister → sistren
Note: Brethren and sistren are antiquated terms that you’re unlikely to encounter or use; however, since these are the only four words in English that use this plural, all four have been included above.

The last category of irregular plurals is borrowed words. These words are native to other languages (e.g., Latin, Greek) and have retained the pluralization rules from their original tongue.

Singular –us; Plural –i cactus → cacti fungus → fungi syllabus → syllabi
Singular –a; Plural –ae formula → formulae vertebra → vertebrae larva → larvae
Singular –ix, –ex; Plural –ices, –es appendix → appendices matrix → matrices index → indices
Singular –on, –um; Plural –a bacterium → bacteria criterion → criteria medium → media
Singular –is; Plural –es thesis → theses analysis → analyses crisis → crises

The rules presented in the table above are almost always followed, but as a borrowed word becomes more popular in its usage, it can be adopted into regular pluralization. For example, formulas and appendixes are accepted words in formal situations. Also, in informal speech, cactuses and funguses are acceptable.

Note: Because of the word’s history, octopuses is preferred to octopi, but octopi is an accepted word.



Look at each word in the table below. Decide whether the word is singular or plural. Then write the other version of the word and explain which rule the plural has used in its formation. For example:

  • stimuli is the plural of stimulus. The singular ends with a -us, so the plural ends with an -i.
  • ox is the singular of oxen. This is an –en noun. To form the plural, an -en was added.
reefs boys waltz
memorandum hypothesis phenomena
focus vertebra appendices
children squid man

There are many to categorize nouns: concrete vs. abstract nouns, common vs. proper nouns, count vs. noncount nouns, and compound vs. non-compound nouns. Let’s take a look at each of these classifications and see exactly what they each mean.

Concrete vs. Abstract Nouns

Concrete nouns are things you can touch, see, hear, or otherwise sense, like booklight, or warmth.

Abstract nouns, on the other hand, are (as you might expect) abstract concepts that can’t be perceived through the senses, such as time and love.

  • concrete noun: rock
  • abstract noun: justice

Common vs. Proper Nouns

Common nouns are generic words, like tissue or watch. They are always lowercase (unless they begin a sentence). A proper noun, on the other hand, is the name of a specific person or thing, like the name John or the brand name Kleenex or Rolex. Proper nouns are always capitalized.

  • common noun: girl
  • proper noun: Ester

Note: This rule also applies to adjectives that are based on proper nouns:

  • It can be difficult to understand Shakespearian language.
  • After her encounter with Lukas, Elisa vowed to hate all Swiss men.

However, if you’re talking about swiss cheesepasteurized milk, and french fries, these adjectives are lowercase. They have a nonliteral meaning: the cheese isn’t really from Switzerland, Louie Pasteur didn’t treat the milk himself, and the fries aren’t really from France.

Count vs. Non-count Nouns

Count nouns are nouns which can be counted. Count nouns can be associated with a numerical value (three whales) in both its singular and plural forms (one fox, two foxes). In some cases, the number can be replaced by the words a, an or the (a fox, an owl, the squirrel).

If a noun cannot have a numerical value nor a plural form, it is called a non-count or mass noun. A person can give another person advice, but they cannot give three advices, because advice has no quantity.

Less or Fewer? Many or Much?

The adjectives less and fewer are both used to indicate a smaller amount of the noun they modify. Many and much are used to indicate a large amount of something. People often use these pairs words interchangeably; however, the words fewer and many are used with count nouns, while less and much are used with non-count nouns:

  • The pet day care has fewer dogs than cats this week.
  • Next time you make these cookies, you should use less sugar.
  • Many poets struggle when they try to determine whether a poem is complete or not.
  • There’s too much goodness in her heart.

You may have noticed that much has followed the adverb too in this example (too much). This is because you rarely find much by itself. You don’t really hear people say things like “Now please leave me alone; I have much research to do.” The phrase “a lot of” has taken its place in current English: “I have a lot of research to do.” A lot of can be used in the place of either many or much:

  • A lot of poets struggle when they try to determine whether a poem is finished or not.
  • There’s a lot of goodness in her heart.



Read the following sentences. Choose the correct words to complete each sentence.

  1. There was (many / much) food at the event. There were (less / fewer) soups than salads and even (less / fewer) desserts.
  2. Miguel loved studying (outer space / outer spaces)—especially different (galaxy / galaxies).
  3. Arturo had too much (water / drinks) before his workout.

Choose the correct word to fill in the blanks in the following sentences:

  1. You can only be in this line if you have fifteen items or _____.
  2. Evelyn was disappointed in the weather forecast; _____ rain was predicted. She preferred dry weather.
  3. I had a lengthy list containing _____ ideas for the project.

Compound Nouns

A compound noun is a noun that is the result of joining together two other words (such as tooth and paste making toothpaste). Let us take for an example, the legend of Bigfoot.

Two images: on the left, a drawing of Bigfoot. On the right, a photo of a girl holding a big show

Figure 1. The famous cryptid Bigfoot on the left is a humanoid figure that apparently lives in Pacific Northwest forests, and is an example of a compound noun. On the right, you would have to have a big foot to wear that shoe.

A compound noun acts like one word, despite being a combination of two. Compound nouns can be classified as closed, hyphenated, or open. A closed compound takes the form of two words put together with no space such as daydream. A hyphenated compound includes two or more words joined by a hyphen such as dry-cleaning. An open compound is two words separated by a space but acting as one unit such as vacuum cleaner.

One common misconception is that compounds are hyphenated or open when one of the root words is longer than one syllable. However, it is important to remember that there are many open or hyphenated compound nouns that have of two single-syllable root words, such as six-pack and full moon.

Some compound nouns differ in writing style depending on who you ask, while others are recently developed, such as e-mail being shortened further to email.

Types of Compound Nouns

  • Solid or Closed form: These compound nouns are defined as being a complete conjoining between the two words that form its makeup. Examples of closed compound nouns include: watermelon, underground, catfish and skydiving.
  • Hyphenated form: Compound nouns that often appear in a hyphenated form are nouns that have suffixes (such as fund-rais(er) and wire-fasten(er)) and nouns that contain articles, conjunctions, or prepositions (such as mother-in-law or build-a-bear)
  • Open or Spaced form: These are compound nouns that are considered to be compound even though they are separated by a space just like any two words. Despite looking like two independent words, they act together as one. Examples of open compound nouns are science fiction, peanut butter, and address book.

Hyphens are often considered a squishy part on language (we’ll discuss this further in Hyphens and Dashes). Because of this, usage differs and often depends on the individual choice of the writer rather than on a hard-and-fast rule. This means open, hyphenated, and closed forms may be encountered for the same compound noun, such as the triplets container ship/container-ship/containership and particle board/particle-board/particleboard. If you’re ever in doubt whether a compound should be closed, hyphenated, or open, dictionaries are your best reference.


The process of making compound nouns plural has its own set of conventions to follow. In all forms of compound nouns, we pluralize the chief element of a compound word (i.e., we pluralize the primary noun of the compound).

  • fisherman → fishermen
  • blackbird → blackbirds
  • brother-in-law → brothers-in-law

The word hand-me-down doesn’t have a distinct primary noun, so its plural is hand-me-downs.


Remember that compounds may be written in three different ways: the solid or closed form, the hyphenated form, and the open or spaced form.


Read the following sentences. Are the compound nouns spelled correctly? How would you create the plural form of each compound noun?

  1. Liam has one sister in law and one brother in law.
  2. High blood pressure can lead to multiple types of heart disease.
  3. When I was four, I aspired to be an astronaut, a fire-fighter, and a sous chef.