thesis

American  

[thee-sis] / ˈθi sɪs /

noun

• theses
  plural

1. a proposition stated or put forward for consideration, especially one to be discussed and proved or to be maintained against objections.

   He vigorously defended his thesis on the causes of war.

   Synonyms:

   proposal, contention, theory

2. a subject for a composition or essay.

3. a dissertation on a particular subject in which one has done original research, as one presented by a candidate for a diploma or degree.

4. Music. the downward stroke in conducting; downbeat.

5. Prosody.

   1. a part of a metrical foot that does not bear the ictus or stress.

   2. (less commonly) the part of a metrical foot that bears the ictus.

6. Philosophy. Hegelian dialectic

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thesis British  

/ ˈθiːsɪs /

noun

1. a dissertation resulting from original research, esp when submitted by a candidate for a degree or diploma

2. a doctrine maintained or promoted in argument

3. a subject for a discussion or essay

4. an unproved statement, esp one put forward as a premise in an argument

5. music the downbeat of a bar, as indicated in conducting

6. (in classical prosody) the syllable or part of a metrical foot not receiving the ictus Compare arsis

7. philosophy the first stage in the Hegelian dialectic, that is challenged by the antithesis

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thesis Cultural  

1. The central idea in a piece of writing, sometimes contained in a topic sentence.

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Usage

Plural word for thesis The plural form of thesis is theses, pronounced [ thee-seez ]. The plurals of several other singular words that end in -is are also formed in this way, including hypothesis/hypotheses, crisis/crises, and axis/axes. A similar change is made when pluralizing appendix as appendices. Irregular plurals that are formed like theses derive directly from their original pluralization in Latin and Greek.

Other Word Forms

Noun Inflected Forms

• theses
  plural

Etymology

Origin of thesis

First recorded in 1350–1400; Middle English, from Latin, from Greek thésis “a setting down, something set down,” equivalent to the- (stem of tithénai “to put, set down”) + -sis noun suffix; see -sis

Explanation

A thesis is the most important or foundational idea of an argument. If the thesis of your paper is that chocolate ice cream is better than vanilla, you'll need to back that up with plenty of sundae-based research. The noun thesis has more than one important sense to it. One definition of thesis is that it is the most important or foundational idea of an argument, presentation, or piece of writing. But it can also mean a large work of art, criticism, or scientific research that represents original research and is generally the final requirement for an academic degree.

Example Sentences

See Examples For:

thesis theses

He found “substantial overlap” with a thesis written by another scholar in 2009.

From Salon ● Aug. 23, 2026

I’ll reveal the company and my full thesis, along with five other stocks currently on my buy list, in the next issue of Let’s Analyze on Substack.

From MarketWatch ● Aug. 18, 2026

Arday, the professor of sociology of education at the prestigious university in eastern England, resigned August 5 after accusations he had plagiarised parts of his doctoral thesis and exaggerated personal achievements prompted a media storm.

From Barron's ● Aug. 17, 2026

The Telegraph, which broke the story that Arday’s thesis had been seemingly plagiarized, wrote at least a dozen news and investigative stories about the scandal in recent weeks.

From The Wall Street Journal ● Aug. 14, 2026

Bentley is thus an advocate of the Thomas thesis: an improved technology for dealing with disease, combined with better scientific knowledge, undermined belief in magic and witchcraft.

From "The Invention of Science" by David Wootton

"There are hundreds of graduate students writing theses on the Maldives using the data they gather together with Monica, or that Monica gathered. And no one knew anything? It makes me laugh."

From BBC ● May 19, 2026

Everyone has their theses, and all are in search of the venue to share them.

From Slate ● Feb. 23, 2026

Since its introduction, fifteen dissertations and final theses at Freie Universität have focused on the topic, along with seven additional dissertations completed by researchers in other countries.

From Science Daily ● Jan. 7, 2026

The program has allowed them to hone their investment theses.

From The Wall Street Journal ● Dec. 15, 2025

The literary theses required by French universities are, as a rule, volumes of several hundred pages, and more important in character even than the German Habilitationsschrift.

From Encyclopaedia Britannica, 11th Edition, Volume 10, Slice 1 "Evangelical Church Conference" to "Fairbairn, Sir William" by Various

Related Words

• contention
• hypothesis
• opinion
• premise
• proposition
• supposition
• theory