lightning (n.) Look up lightning at Dictionary.com
late 13c., ligtnyng, "lightning, a flash of lightning," verbal noun from lightnen "make bright," or else an extended form of Old English lihting, from leht (see light (n.)). Another Middle English word for it was leven (mid-13c.), of uncertain origin, with no apparent source in Old English. (Old English had ligetung "lightning," from liget "lightning, flash of lightning." "Lightning" also was a specialized sense of lihting "lighting" and beorhtnes "brightness.")

Meaning "cheap, raw whiskey" is attested from 1781, also sometimes "gin." Lightning bug is attested from 1778. Lightning rod from 1790.