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

---

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

---

thesis Cultural  

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

---

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

For Alphabet, "this is the first quarter that the negative thesis around AI crushing search has legs," Ives wrote, referring to Google’s search advertising business, one of the most profitable businesses in history.

From Barron's ● Oct. 30, 2026

The essay unfolds as a tent revival for the already converted, with the writers Wes Jackson, Scott Russell Sanders and Robert B. Weeden raising their hands to affirm and extend Berry’s thesis.

From The Wall Street Journal ● Oct. 23, 2026

Not cool because it left her thesis hanging.

From Los Angeles Times ● Oct. 21, 2026

The experiment has spawned a new investment thesis.

From MarketWatch ● Oct. 21, 2026

Almost all his summer had been spent collecting pedantic data for his thesis, and now he was in a mood to think about important facts.

From "Double Helix" by James D. Watson

On the viral Reddit discussion boards, traders outlined their own theses on how Wendy’s could score a turnaround.

From The Wall Street Journal ● Jun. 25, 2026

Notice that many of theses names are software or consumer and business services companies.

From Barron's ● May 13, 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

In the faculty of sciences a candidate for the doctorate may submit two theses, or else submit one thesis and undergo an oral examination.

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

Random Word

Spin the wheel and learn a new word!

---

Related Words

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

---