The Collaborative International Dictionary
Fireball \Fire"ball`\, n.
(Mil.) A ball filled with powder or other combustibles, intended to be thrown among enemies, and to injure by explosion; also, to set fire to their works and light them up, so that movements may be seen.
A rare phenomenon often associated with or caused by lightning, resembling a luminous ball of fire passing rapidly through the air or along solid objects, then disappearing, and sometimes exploding. It seldom lasts more than a few seconds. Also called ball lightning, globe lightning, globular lightning, or kugelblitz.
A large mass of fire caused by a large explosion, as of inflammable liquids or a nuclear device. The larger fireballs, as of nuclear explosions, rise seemingly intact into the air and may reach high altitudes while still glowing.
Wiktionary
n. A short-lived, glowing ball sometimes observed to float in the air and thought to consist of ionized gas associated with thunderstorms
Wikipedia
Ball lightning is an unexplained atmospheric electrical phenomenon. The term refers to reports of luminous, spherical objects which vary from pea-sized to several meters in diameter. Though usually associated with thunderstorms, it lasts considerably longer than the split-second flash of a lightning bolt. Many early reports say that the ball eventually explodes, sometimes with fatal consequences, leaving behind the odor of sulfur.
Until the 1960s, most scientists argued that ball lightning was not a real phenomenon but an urban myth, despite numerous reports from throughout the world. Laboratory experiments can produce effects that are visually similar to reports of ball lightning, but how these relate to the natural phenomenon remains unclear.
Scientists have proposed many hypotheses about ball lightning over the centuries. Scientific data on natural ball lightning are scarce, owing to its infrequency and unpredictability. The presumption of its existence depends on reported public sightings, and has therefore produced somewhat inconsistent findings. Due to inconsistencies and to the lack of reliable data, the true nature of ball lightning remains unknown. The first ever optical spectrum of what appears to have been a ball-lightning event was published in January 2014 and included a video at high frame-rate.
Ball Lightning is a 1979 Czechoslovak comedy film. Screenplay was written by Zdeněk Svěrák, Ladislav Smoljak and Zdeněk Podskalský and film was directed by Smoljak and Podskalský.
Usage examples of "ball lightning".
All the creatures that had been at vigil with him in the night were gone and about him lay only the strange coral shapes of fulgurite in their scorched furrows fused out of the sand where ball lightning had run upon the ground in the night hissing and stinking of sulphur.
Brilliant spots of light are streaking wildly around the inside of the plane, like ball lightning, but--and this is far from obvious at first--they are actually projected against the wall of the plane, like flashlight beams.
Niall had never seen, or even heard of, ball lightning, but he knew instinctively that it could be dangerous.
Though rare, ball lightning was too mundane to satisfy his expectations, and disappointment brought his heart rate almost back to normal.
But whatever softness was there was often overlooked when the observer was pinned by hard eyes the color of ball lightning.
Nine batches in a row, and every one of them producing ball lightning instead of the elixir.