light•ningPronunciation: (līt'ning), [key]
—n., v., -ninged, -ning,
a brilliant electric spark discharge in the atmosphere, occurring within a thundercloud, between clouds, or between a cloud and the ground.
to emit a flash or flashes of lightning (often used impersonally with it
as subject): If it starts to lightning, we'd better go inside.
of, pertaining to, or resembling lightning, esp. in regard to speed of movement: lightning flashes; lightning speed.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.