A discharge of atmospheric electricity, accompanied by a vivid flash of light, commonly from one cloud to another, sometimes from a cloud to the earth. The sound produced by the electricity in passing rapidly through the atmosphere constitutes thunder.
- An abrupt, discontinuous natural electric discharge in the atmosphere.
- The visible flash of light accompanying such a discharge.
- Informal A sudden, usually improbable stroke of fortune.
- To discharge a flash of lightning.
- Moving or occurring with remarkable speed or suddenness.