定理

• Reading: ていり
• Romaji: teiri
• Kanji breakdown: 定 (tei) — fix, establish, decide; 理 (ri) — reason, principle, logic
• Pronunciation: /teː.ɾi/

Meaning

Theorem; a mathematical or logical proposition that has been proven to be true.

A noun used primarily in mathematics and logic to refer to a statement that has been rigorously proven. Well-known examples include ピタゴラスの定理 (Pythagorean theorem) and フェルマーの最終定理 (Fermat's Last Theorem). Distinguished from 定義 (definition) and 公理 (axiom). Typically encountered in academic and educational contexts.

Examples

1. ピタゴラスの定理は中学校で習う基本的な数学だ。 The Pythagorean theorem is a fundamental concept taught in middle school math.
2. この定理を使えば問題がもっと簡単に解ける。 Using this theorem makes the problem much easier to solve.
3. 数学者たちはその定理の証明に何年もかけた。 Mathematicians spent years proving that theorem.

Usage Guide

Context: mathematics, education, science, logic

Tone: academic

Origin & History

From Sino-Japanese 定 (tei, to fix/establish) + 理 (ri, reason/principle). Literally 'an established principle,' reflecting a truth that has been fixed through logical proof.

Cultural Context

Era: Modern

Generation: Students and academics

Social background: Educated