A central angle is an angle whose vertex is located at the center of a circle. It is formed by two radii, which are straight lines that extend from the center to the edge of the circle. The measure of a central angle is directly related to the arc it intercepts on the circle, meaning that larger angles correspond to longer arcs. Central angles are important in various fields, including geometry and trigonometry. They help in calculating the circumference and area of circles, as well as in understanding the properties of related shapes, such as sectors and chords.