from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A rare form of lightning in the shape of a glowing red ball, associated with thunderstorms and thought to consist of ionized gas.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A short-lived, glowing ball sometimes observed to float in the air; thought to consist of ionized gas associated with thunderstorms
from the GNU version of the Collaborative International Dictionary of English
- n. a rare form of lightning sometimes seen as a globe of fire moving from the clouds to the earth.
from The Century Dictionary and Cyclopedia
- n. An electric discharge which appears as a ball of fire descending from the atmosphere to the earth, rolling slowly along the ground or the rigging of a vessel, and eventually exploding violently, leaving a strong sulphurous or ozone odor: a form of natural atmospheric lightning. Although rare, the reality of this phenomenon is supported by several well-authenticated cases.
A calque of German Kugelblitz. (Wiktionary)
Errant orbs of ball lightning burst free, to spend themselves against the insulated ceiling in showers of coruscating sparks.