Grammar Irregular Plurals |
The Blue Book of Grammar and Punctuation

Irregular Plurals

Many nouns in English have a plural form either with an s/es ending or without. For example, when is it correct to use youth vs. youths, fish vs. fishes, or hair vs. hairs?

Use youths and hairs when countable.
Example: Three youths were given awards for community service.

If youth is being used collectively, do not add the s.

Example: The youth of today watch less TV but spend more time on the computer.

When youth is used as a collective noun, you may follow it with either a singular or plural verb. I chose the plural verbs watch and spend because I felt that we were using youth in a plural manner here.

Examples: The hairs on her chin were long.
Her hair is long.

The words fish and fishes are interchangeable, although some references say to use fishes when referring to two or more species.

Examples: This fish is huge.
These barracuda fish are huge.
All the barracuda fish in the reef are enormous.
The fishes in the reef are colorful. (indicating two or more species)

Some nouns do not change at all in their plural form.

Examples: sheep, deer, offspring, series, species

Other nouns have plural forms that do not involve adding an s.

Examples: alumnus/alumni, radius/radii, child/children, woman/women, foot/feet, goose/geese, tooth/teeth, vertebra/vertebrae, mouse/mice

To confuse us even more, some nouns change their is ending in the singular to an es ending in the plural.

Examples: parenthesis/parentheses, paralysis/paralyses, diagnosis/diagnoses

Is there a simple way to know the plural of a noun? Only if you’re psychic. The rest of us are stuck with having to rely on the dictionary.


If the article or the existing discussions do not address a thought or question you have on the subject, please use the "Comment" box at the bottom of this page.

39 responses to “Irregular Plurals”

  1. Karin says:

    Should I use a comma or a semi colon in the following sentence:

    Cathy has closed 2,692 units in 180 separate transactions, totaling $246 million…

  2. Clint says:

    Thanks for the interesting, diverse and thought-provoking blog! I’ll be returning often.

    Clint, enjoying his summer break in Boulder, CO

  3. Jane says:

    I would use a comma after “transactions.”

  4. Abby says:

    Karin, DO NOT use a semicolon in that case. Keep your comma exactly where it is. Semicolons are only used to connect two closely-related, (usually but not always) short sentences. A semicolon is stronger than a comma but weaker than a period, so it is useful and versatile; it can also give your paragraph color by contributing to varied sentence structures. I often use semicolons with cause-effect sentences – in place of the word “because.” For example, “I like dogs; I enjoy their companionship.”

    NOTE: If I were to say, “I like dogs, I enjoy their companionship,” I’d be using a comma splice (using a comma where a sentence should end), and that is incorrect. I see this all the time, so watch out! Most people don’t seem to know that a sentence can only end with a semicolon, period, question mark, exclamation point, or sometimes a dash – NEVER a comma. A comma should only be used before a conjunction in a compound sentence and where you would pause if you were to read a sentence out loud, such as in your sentence above.

  5. Jane says:

    Abby, I agree with your comments to Karin.

  6. Wiotkie Dziecko says:

    Keep on blogging! its getting through the tough times that make you stronger and then the good times will follow, keep writing about your experiences and we should all pull in collaboration.

    • Jane says:

      I don’t know what your advice has to do with grammar, but I needed to hear it for other reasons in my life. So thank you!

  7. Mildred says:

    Thank you for your newsletters; it helps review and understand better the English grammar.
    I bought the Blue Book and I use it constantly to review my work,as I am an editor for children’s books.

    Would you please comment on the use of fruit and fruits? Is it used as a collective noun sometimes?
    For example, a tree with a lot of mangoes; how do I say: “That tree has a lot of fruit/ fruits”? (I want to introduce the word “fruit” to the children)

    • Jane says:

      The word fruit can be used as a collective noun. Examples: Fruit is a healthy snack. That tree has a lot of fruit. Usually when you speak of fruit as a countable noun, you say a piece of fruit, two pieces of fruit, etc. The plural form fruits is not used as often and it generally refers to two or more different kinds of fruit. For example, one might say “The salad bar had a variety of fruits and vegetables.” That would be grammatically correct. But it would also be grammatically correct to say “The salad bar had a variety of fruit and vegetables.” The word fruits is often used along with the word vegetables because it sounds better.

      • Mildred says:

        If the children are looking at the tree full of mangoes (What kind of fruit does the tree have?); then what would be the correct (didactic) way of answering the question? Mango/mangoes.

        • Jane says:

          The question may be answered several ways:
          “The tree has mangoes.” or “The tree has mangoes on it.” (Note: the plural of mango can be mangoes or mangos.)
          “The tree has mango fruit.”
          “The tree has mango fruits.” (The plural form fruits generally, but not always, refers to two or more different kinds of fruit.)
          “That is a mango tree.”

  8. Anderson says:

    Children’s and Student’s Ministry (correct?)

    • Jane says:

      Since you are talking about children and students, the possessives would be children’s and students’. However, I do not know how many ministries you are talking about. If one, you would write: children’s and students’ ministry. If two, write children’s ministry and students’ ministry. If more than two, write either children’s and students’ ministries if children and students are ministered together, or children’s ministries and students’ ministries if they are ministered separately.

  9. Prem Antony says:

    Is it correct to say,for example, variety of papers, types of teachers, etc. It takes double use of plurals!!

    • Using more than one plural word in a sentence is not unusual (the word “variety” in your example, by the way, is not plural). Examples:

      The corner newsstand sells a variety of papers.
      All types of teachers were present at the workshop. OR
      All kinds of teachers were present at the workshop.

  10. xlntgson says:

    Countable, uncountable and collective noun plurals are confusing to lower grades, even advance level students fail to apprehend. Eg. Hair, youth, people and fruit.

    • We think you meant to write the word “comprehend” in your sentence. The plurals for hair and youth are explained in this blog. For more information on the word fruit, please see our blog response of September 27, 2012, to Mildred. The word people is often used synonymously with human beings or persons. The word peoples is defined as “a body of persons that are united by a common culture, tradition, or sense of kinship, that typically have common language, institutions, and beliefs, and that often constitute a politically organized group.”

  11. nasser says:

    Thank you all for your clear, precious comments. I Nasser from syria teacher of english. I am teaching Syrian refugees students in Lebanon; now I am I need sites which help teaching in English through songs and games.

    • We applaud and respect the work you are doing. If you have not already done so, an Internet search for “teaching English through songs and games” yields numerous helpful sites and tools. We wish you the best of luck.

  12. Jane says:

    Is the ‘s correct in the following sentence?

    Here is a copy of Seacoast Youth Services’s invoice# 12.

    • When a company’s name ends in a plural (Services) add only an apostrophe after the s. We recommend using a space between the word invoice and #12.
      Here is a copy of Seacoast Youth Services’ invoice #12.

  13. Rhonda F. says:

    I ordered your book and I love it. But I couldn’t find anything in it about when to use lives vs lifes. Is lives always used when using the plural of life? For example: The girl believed she had lived many lives. Or would it be: The girl believed she had lived many lifes.

    • We’re happy to hear you love The Blue Book.

      The plural of the word “life” is almost always “lives.” One exception we can think of: the plural of still life is still lifes.

  14. Alfred Tsebo says:

    This Is very interesting and I’ve been having issues too on using the apostrophe as some other times I’ll just use it unnecessary.

    On Rhonda’s Statement, I’d like to believe that ” the girl believes she had lived many lifes” is correct regardless of the original plural form because using “lives” sounds a bit inappropriate.

  15. Sandra T says:

    I have a program called “Youths of Today”. This is a general name I gave to it because I deal with topics pertaining to all youth. It is therefore a program reaching out to the youths. I would like to know if the program should be called Youth or Youths of Today? With or without the ‘s’

  16. Diana McIntyre-Pike says:

    I am having a struggle with colleagues of mine with the word youth being documented as youths which I was taught that this is not correct. Could you please advise me if it has now changed?

    • The word choice depends on the sentence. As mentioned above, use youths when countable; if youth is being used collectively, do not add the s. Our post Stubborn Stinkaroos says, “There aren’t many synonyms for children. After kids, young people, and youngsters, the pickings get slim, especially if you eschew cutesy-poo. So, rejecting non-options like little ones, tykes, and tots, many writers eventually come around to youth. Trouble is, youth is singular; it’s cheesy to say, ‘Youth today are facing new challenges.’ The obvious fix is ‘youths today,’ even though a lot of scribes think ‘youths’ is clunky.”

  17. Kurt says:

    I have a piece of equipment with model name D13. How do I pluralize this (e.g., I have two ___)?

    Singular possessive would be D13’s. How would I show a plural possessive for multiple D13 units (e.g., the ___ power source)?

    Similarly, what if the model ends in ‘s’. Same questions as above for model M35s.

    • The plural is written I have two D13s. For singular possessive, use an apostrophe D13’s. To show plural possessive write the D13s’ power source. For a model named M35s, you could write the following:
      M35ses (plural) OR M35s models may be less confusing
      M35s’s (singular possessive) OR M35s model’s
      M35ses’ (plural possessive) OR M35s models’

      Also see Apostrophes with Words Ending in s for more information.

  18. Zeyad Zaki says:

    Is it correct to say “refugees kids”?

  19. Mujtaba says:

    What is correct “from the depth of our hearts” or “from the depths of our hearts”?

  20. Michael Mason says:

    From the depths of our hearts or from the depth of our heart?

  21. Tony says:

    I have a question…. would it be “male youth’s experiences of playing football are” or “male youths’ experiences of playing football are” (e.g. where does the apostrophe go when discussing about plural youth in a possessive sense). Thanks.

    • Our Rule 2a of Apostrophes says, “Regular nouns are nouns that form their plurals by adding either the letter s or es (guy, guys; letter, letters; actress, actresses; etc.). To show plural possession, simply put an apostrophe after the s.” Therefore, male youths’ is correct.

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