A toroid is a three-dimensional geometric shape resembling a doughnut or a ring, formed by revolving a circle around an axis that is coplanar with the circle but does not intersect it. Mathematically, it can be described by its major and minor radii, which define the size of the toroid and the thickness of the ring, respectively. Toroids are commonly encountered in various fields, including physics and engineering, particularly in the design of inductors and magnetic fields.