from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Either of two torus-shaped areas of high-energy charged particles which partly surround Earth, trapped by its magnetic field. The areas are characterised by intense radiation. When the belts "overload", particles strike the upper atmosphere and fluoresce, causing the polar aurora.
- n. Any of similar areas around another planet.
From James Alfred Van Allen, US physicist. (Wiktionary)