theorem; proposition
A mathematical or logical statement that has been proven or is presented for proof. In everyday contexts, it can also refer to a firmly established principle.
The Pythagorean theorem applies to right triangles.
It took several hours to prove this theorem.
binomial theorem
trigonometric addition formulas
four-color theorem; four-color map theorem
factor theorem
reciprocity theorem
From 定 (fixed, established) + 理 (principle, logic). The term was coined in Japanese to translate Western mathematical concepts during the Meiji period.