Definition of

# Theory

A set of ideas that explain something.

In

In

But in

In

**Mathematics**a theory is the set of theorems and principles that make up a branch of mathematics, such as Number Theory, Set Theory, etc.In

**Science**a theory is well understood, has been properly examined, and can be tested again and again and always works, such as the Theory of Gravity.But in

**everyday language**a theory is an explanation that may be true but has**not**been properly tested. So be careful about this confusing difference!See: Theorem

Copyright © 2018 MathsIsFun.com