diédro

A diédro, also known as a dihedral angle, is a geometric concept referring to the angle between two intersecting planes. Imagine two flat surfaces that meet along a line. The space enclosed between these two planes, measured from the line of intersection outwards, forms the diédro.

In mathematics, a diédro is often defined by the line of intersection and a point on that line. From that point, two rays are drawn, one in each plane, perpendicular to the line of intersection. The angle between these two rays is the measure of the diédro. This angle can be expressed in degrees or radians.

Diédros are fundamental in various fields of geometry and its applications. In crystallography, diédral angles are used to describe the angles between crystal faces. In surveying and navigation, they are crucial for measuring angles in three-dimensional space. Architecture and engineering also utilize the concept of diédros when designing structures and analyzing forces. The concept is essentially about the "opening" between two surfaces that share a common edge.