theorem

noun

the·​o·​rem ˈthē-ə-rəm 

ˈthir-əm

1

: a formula, proposition, or statement in mathematics or logic deduced or to be deduced from other formulas or propositions

2

: an idea accepted or proposed as a demonstrable truth often as a part of a general theory : proposition

the theorem that the best defense is offense

3

: stencil

4

: a painting produced especially on velvet by the use of stencils for each color

theorematic

ˌthē-ə-rə-ˈma-tik 

ˌthir-ə-

adjective

Examples of theorem in a Sentence

Recent Examples on the Web

What’s more, this theorem has implications for nuclear fusion. —Manon Bischoff, Scientific American, 9 June 2026

In a typical math paper, lemmas — simpler results that help build toward the proof of a larger theorem — might be about 20 lines long, but for the PFR formalization, Tao broke the proof down into five-line lemmas. —Quanta Magazine, 8 June 2026

And almost every theorem built on top was resting on foundations no one had formally examined. —Nick Lichtenberg, Fortune, 1 June 2026

Using insights from number theory, including Jacobi’s two-square theorem, Erdős was able to show that an optimally sized circle will enable the number of unit-distance pairs to grow faster than the number of points, but only barely. —ArsTechnica, 1 June 2026

Word History

Etymology

Late Latin theorema, from Greek theōrēma, from theōrein to look at, from theōros spectator, from thea act of seeing — more at theater entry 1

First Known Use

1551, in the meaning defined at sense 1

Phrases Containing theorem

• Bayes's theorem
• Bayes theorem
• binomial theorem
• central limit theorem
• DeMoivre's theorem
• Fermat's last theorem
• Fourier's theorem
• Godel's theorem
• Jordan curve theorem
• mean value theorem
• Pythagorean theorem
• remainder theorem
• Rolle's theorem

Rhymes for theorem

• serum

Kids Definition

theorem

noun

the·​o·​rem ˈthē-ə-rəm 

ˈthi(-ə)r-əm

1

: a formula, proposition, or statement in mathematics or logic that has been or is to be proved from other formulas or propositions

2

: an idea accepted or proposed as a demonstrable truth