Have you ever wondered whether appendices or appendixes is the correct plural of appendix? You’re not alone. Many students, writers, and professionals search for the plural of appendix because both words appear in dictionaries, books, and online articles.
The good news is that both appendices and appendixes are correct, but they are often used in different situations. Knowing when to use appendices and when to use appendixes can make your writing clearer and more accurate.
In this guide, you’ll learn the difference between appendices vs. appendixes, their meanings, the grammar rule behind the two forms, and plenty of real-life examples. Whether you’re writing an academic paper, a business report, or simply improving your English grammar, this article will help you choose the right plural with confidence.
Quick Answer
Both appendices and appendixes are correct plurals of appendix. Appendices is the preferred form in academic writing, formal English, and medical terminology, while appendixes is also accepted, especially for the supplementary sections of books, reports, and business documents. The best choice depends on your writing context, audience, and the style guide you are following.
What Does “Appendix” Mean?
An appendix is a noun with two common meanings in English grammar and everyday language. First, it can refer to a supplementary section added to the end of a book, report, research paper, or business document.
This section usually includes extra information, charts, tables, or references that support the main text. Second, an appendix is a small organ attached to the large intestine in the human body.
Understanding the appendix definition makes it easier to choose the correct plural of appendix. Whether you are talking about books or anatomy, the singular form remains appendix, while the plural may be appendices or appendixes, depending on the context. Knowing this basic meaning is the first step toward using both forms correctly.
Is the Correct Plural “Appendices” or “Appendixes”?
The simple answer is that both appendices and appendixes are correct. Many people wonder, “Is it appendices or appendixes?” because they see both forms in dictionaries and published writing.
Appendices follows the original Latin plural pattern and is commonly used in academic writing, formal documents, and medical terminology. Appendixes follows the regular English plural rule by adding -es and is also accepted by major dictionaries.
Today, writers can use either form, but the best choice depends on the audience and writing style. If you are preparing a research paper, appendices is usually preferred. For general English or business writing, appendixes is also considered correct and natural.
Why Does “Appendix” Have Two Plural Forms?
The reason appendix has two accepted plurals is its history. The word comes from Latin, where many nouns formed their plurals differently from modern English. Because of this, appendices became the traditional Latin plural.
As English developed, many borrowed words also gained regular English plurals, creating appendixes. This pattern appears with several other words that have both Latin and English endings. Over time, dictionaries accepted both versions because each became common in different situations.
This is why appendices vs. appendixes is not a question of right or wrong. Instead, it is about choosing the form that best matches your writing style, audience, and purpose while following accepted grammar rules.
When Should You Use “Appendices”?
Use appendices when writing in formal, academic, or professional settings. Universities, research journals, and scientific publications often prefer this form because it follows the traditional Latin plural.
For example, a thesis may include several appendices containing survey results, interview transcripts, or detailed calculations. Medical professionals may also use appendices when discussing more than one appendix in technical writing. If you are following a style guide for research or scholarly work, this is usually the safest choice.
Learning when to use appendices helps your writing sound polished and consistent. If you enjoy improving your grammar skills, you may also like our guide on Traveler or Traveller, which explains another common difference in English usage.
When Should You Use “Appendixes”?
Although appendices is often preferred in formal writing, appendixes is also a correct plural. It is commonly used in general English, business reports, manuals, and everyday communication. Many writers choose appendixes because it follows the standard English rule for making nouns plural, making it easy to recognize.
If your audience is the general public rather than an academic community, appendixes may sound more natural and approachable. The important thing is to stay consistent throughout your document instead of switching between both forms.
Understanding when to use appendixes allows you to write with confidence while matching the tone of your content. Both forms are accepted, so context should guide your decision.
Appendices vs. Appendixes in Academic, Business, and Medical Writing
Choosing between appendices and appendixes often depends on the type of writing and the audience. In academic writing, appendices is generally preferred because it fits formal style and is widely used in textbooks, research papers, and university assignments.
For business writing, however, both forms are acceptable. The spelling appendixes is also common in reports and workplace documents. In medical terminology, appendices is usually favored because of its Latin origin and long-standing use in scientific literature.
Whichever form you choose, the most important thing is to remain consistent throughout your writing. If you enjoy learning about commonly confused English words, our guide on Led or Lead can also help you understand the correct usage with clear examples.
Examples of Appendices and Appendixes in Sentences
Seeing both words in real sentences makes it much easier to understand appendices vs. appendixes. In academic writing, you might write, “The appendices include the survey questions and interview results.” A medical journal could say, “The surgeons examined several appendices during the study.”
In everyday or business writing, you may read, “The report contains three appendixes with supporting charts.” Another example is, “Please check the appendixes for additional project details.”
These examples show that both appendices and appendixes are correct plurals of appendix. The best option depends on your audience, writing style, and purpose. Reading examples in different contexts helps you choose the correct plural of appendix with confidence.
Common Mistakes People Make
Many writers make small mistakes when using the plural of appendix because both forms are accepted. One common error is believing that appendixes is incorrect. In fact, major dictionaries recognize it as a proper English plural.
Another mistake is thinking appendices should always be used, even in casual or business writing. Some people also switch between appendices and appendixes in the same document, which can confuse readers.
It is better to choose one form and use it consistently throughout your writing. Finally, avoid using appendixs, as this spelling is incorrect. Understanding these common mistakes will help you write clearer, more professional English while following accepted grammar rules.
Similar English Words with Two Accepted Plurals
Appendix is not the only English word with two accepted plural forms. Several words borrowed from Latin have both traditional and modern English plurals. For example, indexes and indices are both correct, while cactuses and cacti are also accepted.
You may also see formulas and formulae, syllabuses and syllabi, or octopuses and octopi, although some are more common than others depending on the situation. Like appendices and appendixes, the preferred form often depends on the audience and writing style.
Knowing these patterns makes it easier to understand irregular plurals and improves your overall English grammar skills for both formal and everyday writing.
Tips to Remember the Difference
A simple way to remember the difference is to think about where you are writing. If you are preparing a research paper, university assignment, or medical document, choose appendices because it is more common in formal writing.
If you are creating a business report, user guide, or general document, appendixes is also a correct and natural choice. Another helpful tip is to check the style guide your school, company, or publisher follows before making a final decision.
Most importantly, stay consistent throughout your document. Remember this easy rule: formal and academic writing usually favors appendices, while general English often accepts appendixes. This simple trick helps you choose the correct plural every time.
FAQs
Can I use both appendices and appendixes?
Yes. Both are accepted by major dictionaries and are considered correct.
Which plural is more common in academic writing?
Appendices is usually preferred in research papers, textbooks, and scholarly publications.
Is appendixes wrong?
No. Appendixes is a correct English plural and is widely used in business and everyday writing.
What is the plural of the body organ appendix?
In medical writing, appendices is generally the preferred form.
Why are there two plural forms?
The word comes from Latin, but English later adopted the regular plural appendixes, so both forms became acceptable.
Conclusion
Choosing between appendices and appendixes does not have to be confusing. Both forms are correct, and major dictionaries recognize each as the correct plural of appendix. The main difference is how they are used.
Appendices is generally preferred in academic writing, formal documents, and medical terminology, while appendixes is common in general English, business reports, and everyday communication.
By understanding the meaning of appendix, the grammar behind its two plural forms, and the situations where each is most appropriate, you can write with greater confidence. When in doubt, consider your audience, follow the required style guide, and stay consistent throughout your document for clear, professional, and effective writing.