In mathematics, the term denotes a side of a right triangle. Specifically, it refers to either of the two sides that form the right angle. The side opposite the right angle is termed the hypotenuse. Consider a right triangle with sides measuring 3 units and 4 units that form the right angle; these are the legs. The hypotenuse would measure 5 units.
Understanding this element is fundamental to trigonometry and geometry. It is critical for applying the Pythagorean theorem, which states the sum of the squares of the lengths of these sides equals the square of the length of the hypotenuse. This relationship enables the calculation of unknown side lengths in right triangles, essential in fields ranging from construction to navigation.