A dyson sphere is a hypothetical, technologically advanced super structure that envelopes an entire star, harnessing the immense power-source within. They are commonly seen as the mark of a Type-2 (or greater) civilization on the Kardashev scale.

Dyson spheres are often depicted as a series of rings or a gargantuan spherical cage, but the exact shape it takes is irrelevant to its classification. As long as it encircles the entire star with the implied function of gathering power from it, it is considered a dyson sphere.