a rare form of lightning in which a persistent and moving luminous white or colored sphere is seen. It can last from a few seconds to several minutes, and travels at about walking pace. Spheres have been reported to vanish harmlessly, or to pass into and out of rooms-leaving, in some cases, sign of their passage such as a hole in a window pane. Sphere dimensions vary but are most commonly from 4 to 8 inches (10-20 cm)

A rare form of lightning in the shape of a glowing red ball that can last anywhere from a few seconds to several minutes. Typically associated with Thunderstorms, these spheres are thought to consist of ionized gas.

A relatively rare form of lightning, consisting of a reddish, luminous ball, of the order of one foot in diameter, which may move rapidly along solid objects or remain floating in mid-air. Hissing noises emanate from such balls and they sometimes explode noisily, but may disappear noiselessly.

Ball lightning reportedly takes the form of a glowing, floating object often the size and shape of a basketball, but it can also be golf ball sized or smaller. It is sometimes associated with thunderstorms, but unlike lightning flashes arcing between two points, which last a small fraction of a second, ball lightning reportedly lasts many seconds. There have been some reports of production of a similar phenomenon in the laboratory, but some still disagree on whether it is the same phenomenon.