When discussing academic writing, one word that often appears is thesis. It represents a central idea or argument, typically used in academic settings, especially at the undergraduate, graduate, or doctoral level. However, when more than one thesis is involved, many people become unsure of how to form the correct plural. Is it thesises? Is there an irregular form? Understanding the plural form of thesis is important for students, researchers, and writers who want to use precise language and maintain grammatical accuracy in their work.
What Is the Plural of Thesis?
The correct plural form of thesis istheses.This follows a pattern common in words borrowed from Greek. In Greek, nouns that end in -is often change to -es in the plural. So just like crisis becomes crises, the word thesis becomes theses.
This is considered an irregular plural in English because it does not follow the common -s or -es rule used for regular nouns. That’s why it can cause confusion for native and non-native speakers alike. Nonetheless, theses is the grammatically correct and widely accepted plural form.
Why Not Use Thesises?
It might seem logical to add -es” to the end of thesis to form thesises, especially since many English words follow this rule. However, that would be incorrect. The word thesis comes from Greek, and English retains its original plural pattern. Therefore, using thesises is a grammatical mistake, and it is not recognized in formal or informal writing.
Examples of Incorrect and Correct Usage
- Incorrect The students submitted theirthesiseson Friday.
- Correct The students submitted theirtheseson Friday.
It’s helpful to memorize irregular plural forms like these, especially if you’re involved in academic or professional writing.
How to Use Theses in a Sentence
Once you understand the plural form, the next step is using it properly within sentences. Here are a few examples that illustrate how theses fits into different grammatical contexts
- Many graduate students struggle to complete theirthesesbefore the deadline.
- The university archives contain hundreds oftheseswritten over the past decade.
- Both authors presented theirthesesat the academic conference.
Each of these examples uses theses as the plural form to indicate multiple research papers or academic arguments. These sentences are grammatically correct and clearly understood in context.
Origin and Meaning of Thesis
To understand why the plural is theses, it helps to look at the word’s origin. The word thesis comes from the Greek wordthesis, meaning a placing or a proposition. In English, it has evolved to mean a formal statement or theory that is put forward as a premise to be maintained or proved.
In academic contexts, a thesis is a document submitted in support of candidature for an academic degree or professional qualification. It represents the author’s research and findings on a particular topic. Thus, the plural theses refers to more than one such document or proposition.
Other Words with Similar Plural Forms
English has several other words with Greek or Latin roots that change form in the plural. Becoming familiar with them can make it easier to remember the correct plural of thesis.
Examples of Irregular Plurals
- Crisis→Crises
- Analysis→Analyses
- Diagnosis→Diagnoses
- Parenthesis→Parentheses
- Hypothesis→Hypotheses
All of these words follow the -is to -es rule, just like thesis becomes theses. Memorizing these can reinforce the pattern and reduce the chance of errors.
When Should You Use Thesis and When Theses?
Use thesis when you are referring to a single work or idea. Use theses when referring to more than one. Here is a quick guide
- One document Her thesis focused on environmental policy.
- Multiple documents Their theses were reviewed by a panel of experts.
It’s a simple distinction, but an important one to get right in both speech and writing.
Tips for Remembering the Plural of Thesis
Since irregular plurals can be tricky, here are a few strategies to help you remember that the correct plural of thesis is theses
- Associate it with similar words like crisis/crises.
- Practice using it in multiple sentences until it feels natural.
- Avoid forming plurals by sound alone what sounds right isn’t always right in English.
- Keep a list of irregular plurals you encounter often.
These habits can improve your confidence and accuracy, particularly in academic settings where correct grammar matters.
Why Plural Accuracy Matters in Academia
In academic writing, grammar and precision are critical. Using the correct plural form, such as theses, reflects your attention to detail and understanding of academic conventions. A mistake like writing thesises can undermine your credibility and distract readers from your ideas.
Whether you are submitting a paper, writing a research proposal, or editing a colleague’s work, using proper plural forms ensures professionalism and clarity. Moreover, correct usage demonstrates respect for the subject matter and for the linguistic traditions embedded in scholarly writing.
The plural form of thesis istheses, following an irregular pattern based on its Greek origin. While it may be easy to assume that thesises is correct, doing so results in a grammatical error. Understanding this distinction is essential for anyone involved in education, writing, or academic research. By remembering and practicing the correct form, you enhance your communication skills and ensure your writing remains professional and accurate. So, the next time you refer to more than one thesis, make sure to use theses with confidence and correctness.