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

Oppenheimer analyst Kristen Owen wrote last month that Corteva recently “presented a solid standalone investment thesis built on the diversity and balance of its portfolio and innovation pipeline.”

From MarketWatch ● Oct. 1, 2026

Purdom had said herself that Hyphenbox was pretty far from her climate thesis.

From The Wall Street Journal ● Sep. 25, 2026

The analyst’s thesis on these companies is in line with what he views to be a broader industry trend, which is that cybersecurity companies are still “accelerating nicely” but expectations may have gotten too high.

From MarketWatch ● Sep. 17, 2026

But that’s the thing about academic research: When you go looking for specific details, they tend to evade you — something that’s easy to forget for those of us who have stopped writing thesis papers.

From Salon ● Sep. 7, 2026

"But I have to figure out a thesis."

From "We Are Okay" by Nina LaCour

Investors will be scrutinising whether the company can navigate theses issues, such as shifting logistics out of China to avoid the US and EU's import fees, Deglise-Favre said.

From BBC ● Aug. 31, 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

All these theses were introduced in the trial.

From The History of the Inquisition of Spain from the Time of its Establishment to the Reign of Ferdinand VII. by Juan Antonio Llorente

Related Words

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