What’s the plural of “thesis”?
A thesis is “a long piece of writing on a particular subject, especially one that is done for a higher college or university degree.” The plural of thesis is theses (pronounced thee-seez).
She submitted her thesis on quantum mechanics.
The professor supervised several theses this year.
He wrote two thesis during his studies.
The students presented their thesises at the conference.
- Thesis is singular.
- The plural of thesis is theses (thee-seez).
Nouns that end in –sis
Many Greek-origin nouns ending in -sis form their plural by replacing -is with -es. Examples include analysis → analyses, crisis → crises, oasis → oases, synopsis → synopses, and thesis → theses.
| Noun: thesis | Example sentences |
|---|---|
| thesis |
She defended her thesis on renewable energy last spring. The student's thesis argued for a new interpretation of the sources. A clear thesis statement helps structure the entire paper. His advisor helped refine the central thesis before submission. |
| theses (plural) |
The department archive contains dozens of graduate theses. Several theses examined similar methodologies across disciplines. Evaluation committees reviewed the final theses this term. |
Synonyms, nearby words, and etymology
thesis
Similar words
- dissertation
- paper
- treatise
- essay
- argument
- proposition
Thesis comes from Greek θέσις (thésis), meaning “a proposition, a setting down, position, thesis,” from the root τίθημι (títhēmi), “I put, place, set.”
Exercise: Irregular, Greek plurals
Choose the correct plural: thesis → ______
Choose the correct plural: diagnosis → ______
Choose the correct plural: oasis → ______
Choose the correct plural: analysis → ______
Early ______ can improve patient outcomes.
FAQs
Q: What is the plural of “thesis”?
Q: How do you pronounce “theses”?
Q: Is “thesises” ever correct?
Q: What are some related words?
Q: What is the origin of “thesis”?
Sources
- “Hypothesis, N.” Oxford English Dictionary, Oxford UP, June 2025, https://doi.org/10.1093/OED/8518699255.
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