Theorem (noun)

A mathematical statement or proposition that has been proven to be true, based on previously established mathematical principles or axioms.

Origin:

Derived from the greek word 'theorema' meaning 'observation' or 'spectacle'.

Examples:

1. Einstein's theory of relativity can be expressed as a set of mathematical theorems.
2. The theorem of Pythagoras states that the square of the length of the hypotenuse of a right-angled triangle is equal to the sum of the squares of the other two sides.
3. The theorem was first proven by Euclid over two thousand years ago.
4. The mathematician spent hours trying to prove the theorem, but couldn't find a solution.
5. The theorem is used to make predictions about the behavior of physical systems and is widely used in engineering and physics.