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

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

For example, results like the fundamental theorem of algebra, whose proof tripped up even mathematical giants like Carl Friedrich Gauss, end up with very simple proofs once topological arguments come into play. —Konstantin Kakaes, Quanta Magazine, 20 May 2026

Your proof rests on two famous sets of premises—Gödel’s incompleteness theorems, which found that every mathematical system will have statements that can never be proven, and Turing’s undecidability result for the halting problem, which found that some problems are inherently unsolvable. —IEEE Spectrum, 4 May 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