theorem
UK: ˈθɪərəm | US: ˈθiːərəm
n. a general proposition or statement in mathematics or logic that can be proved by reasoning
n. an idea or principle accepted as demonstrably true
The word theorem traces back to Greek theōrēma, meaning "a spectacle, something to be looked at." In ancient Greek mathematics, a theorem was a proposition observed (theo-) and then logically demonstrated, akin to visually inspecting a geometric figure. Over time, it evolved into its modern sense of a provable statement in formal systems.
Pythagoras' theorem is fundamental in geometry.
The mathematician spent years proving the new theorem.
This theorem underpins much of modern algebra.
The professor explained the theorem with a simple diagram.
Without this theorem, the entire proof collapses.