Merriam-Webster Logo
  • Dictionary
  • Thesaurus
  • Scrabble
  • Spanish Central
  • Learner's Dictionary


noun, the·sis \ˈthē-səs, British especially for 1 ˈthe-sis\

Simple Definition of thesis

  • : a long piece of writing on a particular subject that is done to earn a degree at a university

  • : a statement that someone wants to discuss or prove

Source: Merriam-Webster's Learner's Dictionary

Full Definition of thesis

plural theses play \ˈthē-ˌsēz\

  1. 1a (1) :  the unstressed part of a poetic foot especially in accentual verse (2) :  the longer part of a poetic foot especially in quantitative verseb :  the accented part of a musical measure :  downbeat — compare arsis

  2. 2a :  a position or proposition that a person (as a candidate for scholastic honors) advances and offers to maintain by argumentb :  a proposition to be proved or one advanced without proof :  hypothesis

  3. 3 :  the first and least adequate stage of dialectic — compare synthesis

  4. 4 :  a dissertation embodying results of original research and especially substantiating a specific view; especially :  one written by a candidate for an academic degree

Examples of thesis in a sentence

  1. She wrote her thesis on Renaissance Nativity scenes.

  2. a master's thesis on the effects of global warming

  3. New evidence supports his thesis.

  4. We disagreed with the basic thesis of the report.

  5. The book's central thesis is that propaganda influences the masses in important ways.

Origin of thesis

in sense 1, Middle English, lowering of the voice, from Late Latin & Greek; Late Latin, from Greek, downbeat, more important part of a foot, literally, act of laying down; in other senses, Latin, from Greek, literally, act of laying down, from tithenai to put, lay down — more at do

First Known Use: 14th century

Rhymes with thesis

THESIS Defined for Kids


noun the·sis \ˈthē-səs\

Definition of thesis for Students

plural theses \-ˌsēz\

  1. 1 :  a statement that a person wants to discuss or prove

  2. 2 :  an essay presenting results of original research

Seen and Heard

What made you want to look up thesis? Please tell us where you read or heard it (including the quote, if possible).


a timid, meek, or unassertive person

Get Word of the Day daily email!


Take a 3-minute break and test your skills!


Which of these is a synonym of nonplus?

disapprove soothe perplex reduce
Name That Thing

Test your visual vocabulary with our 10-question challenge!


Test Your Knowledge - and learn some interesting things along the way.