thesis

American  

[thee-sis] / ˈθi sɪs /

noun

plural

theses

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.

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; -sis

Example Sentences

That there are meaningful connections between religion and baseball—the thesis of the docu-lecture “Baseball: Beyond Belief”—seems obvious.

From The Wall Street Journal • Apr. 2, 2026

Resting state citizenship on residency reinforces the thesis that citizenship generally requires residence, not mere presence.

From The Wall Street Journal • Mar. 31, 2026

She said she was also supposed to deliver a guest lecture on her thesis, cat-sit for a friend and pick up her books.

From BBC • Mar. 27, 2026

“I am more cautious than ever because the risk of stagflation, geopolitical tensions and AI makes it hard for me to decide what a long-term thesis would look like,” said retail investor Duncan Forbes.

From MarketWatch • Mar. 25, 2026

“It depends on how you frame it. What's your angle, your thesis statement? What are you trying to say?”

From "Pride" by Ibi Zoboi

Related Words

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