plural theses
ˈthē-ˌsēz 
1
: a dissertation (as by a candidate for an academic degree) presenting results of original research and usually providing evidence to support a specific view
2
a(1)
: an idea put forth for discussion or proof : hypothesis
… a decade or more before John Tyndall began to explore the thesis that slight changes in the atmosphere's composition could cause climatic variations.—
Leo Hickman
Leo Hickman
(2)
: a central idea or theme (as of an artistic work)
The song's hook … speaks to the album's thesis …—Bobby Olivier
Bobby Olivier
b
often thesis statement
(1)
: a statement that introduces the thesis or main idea of a piece of writing
the report's opening thesis
A compelling thesis statement forms the backbone of your essay, expressing the main argument or point of view.—Helen Garcia
Helen Garcia
(2)
: a statement of the central idea or theme (as of an artistic work)
… "The future sucks" might as well be the movie's thesis …—Dan Caffrey
Dan Caffrey… Deanna … delivers the line of the night: "I want to live." That really is the thesis statement of the episode.—John Saavedra
John Saavedra3
4
: the first and least adequate stage of dialectic compare synthesis
Did you know?
In high school, college, or graduate school, students often have to write a thesis on a topic in their major field of study. In many fields, a final thesis is the biggest challenge involved in getting a master's degree, and the same is true for students studying for a Ph.D. (a Ph.D. thesis is often called a dissertation). But a thesis may also be an idea; so in the course of the paper the student may put forth several theses (notice the plural form) and attempt to prove them.
Examples of thesis in a Sentence
She wrote her thesis on Renaissance Nativity scenes.
a master's thesis on the effects of global warming
New evidence supports his thesis.
We disagreed with the basic thesis of the report.
The book's central thesis is that propaganda influences the masses in important ways.
Recent Examples on the Web
At the core of their thesis was the idea that many of the geographic linkages that had long bound certain industries to certain regions – like automotive in Michigan and meatpacking in the Midwest – were weakening.
—Christopher Briem, The Conversation, 25 Mar. 2026
His core thesis was that the president’s formal constitutional powers are constrained, with their effectiveness reliant on their ability to bargain and persuade other key political players.
—Jeffrey Sonnenfeld, Fortune, 23 Mar. 2026
Africa and the broader Global South are central to this migration thesis.
—Wyles Daniel, USA Today, 23 Mar. 2026
The material is stronger under compression perpendicular to the grain than the original spruce timber, explains Ronny Kürsteiner, who developed the process as part of his doctoral thesis.
—Bojan Stojkovski, Interesting Engineering, 22 Mar. 2026
See All Example Sentences for thesis
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Christopher Briem, The Conversation, 25 Mar. 2026
His core thesis was that the president’s formal constitutional powers are constrained, with their effectiveness reliant on their ability to bargain and persuade other key political players.
—Jeffrey Sonnenfeld, Fortune, 23 Mar. 2026
Africa and the broader Global South are central to this migration thesis.
—Wyles Daniel, USA Today, 23 Mar. 2026
The material is stronger under compression perpendicular to the grain than the original spruce timber, explains Ronny Kürsteiner, who developed the process as part of his doctoral thesis.
—Bojan Stojkovski, Interesting Engineering, 22 Mar. 2026
See All Example Sentences for thesis
Cite this Entry
“Thesis.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/thesis. Accessed 26 Mar. 2026.
Copy CitationKids Definition
thesis
noun
the·sis
ˈthē-səs
plural theses
ˈthē-ˌsēz
1
: a statement put forth for discussion or proof : hypothesis
2
: a long essay presenting the results of original research
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