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

The two decided to formalize Viazovska’s proofs by translating every term, definition and theorem referenced into Lean code. —Manon Bischoff, Scientific American, 26 Mar. 2026

For one thing, every new proof in Lean can only use formal definitions and theorems that have already been verified and stored in its library. —Leila Sloman, Quanta Magazine, 25 Mar. 2026

Yet their queries extend beyond asking a chatbot to define the Pythagorean theorem or to explain the significance of Boo Radley’s character in To Kill a Mockingbird. —Jake Angelo, Fortune, 25 Feb. 2026

In the mid-Aughts, armed with the theorem, the rationalists discovered that humanity is in jeopardy of a rogue superintelligent AI wiping out all life on the planet. —Sam Kriss, Harpers Magazine, 24 Feb. 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

• variorum
• antiserum
• serum
• thiram

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