What is "sheet lightning"

Sheet \Sheet\, n. [OE. shete, schete, AS. sc[=e]te, sc[=y]te, fr. sce['a]t a projecting corner, a fold in a garment (akin to D. schoot sheet, bosom, lap, G. schoss bosom, lap, flap of a coat, Icel. skaut, Goth. skauts the hem of a garment); originally, that which shoots out, from the root of AS. sce['o]tan to shoot. [root]159. See Shoot, v. t.] In general, a large, broad piece of anything thin, as paper, cloth, etc.; a broad, thin portion of any substance; an expanded superficies. Specifically: (a) A broad piece of cloth, usually linen or cotton, used for wrapping the body or for a covering; especially, one used as an article of bedding next to the body. He fell into a trance, and saw heaven opened, and a certain vessel descending unto him, as it had been a great sheet knit at the four corners. --Acts x. 10, 1

1. If I do die before thee, prithee, shroud me In one of those same sheets.
   --Shak. (b) A broad piece of paper, whether folded or unfolded, whether blank or written or printed upon; hence, a letter; a newspaper, etc. (c) A single signature of a book or a pamphlet; in pl., the book itself.

   To this the following sheets are intended for a full and distinct answer.
   --Waterland. (d) A broad, thinly expanded portion of metal or other substance; as, a sheet of copper, of glass, or the like; a plate; a leaf. (e) A broad expanse of water, or the like. ``The two beautiful sheets of water.''
   --Macaulay. (f) A sail.
   --Dryden. (g) (Geol.) An extensive bed of an eruptive rock intruded between, or overlying, other strata.

2. [AS. sce['a]ta. See the Etymology above.] (Naut.)

   1. A rope or chain which regulates the angle of adjustment of a sail in relation in relation to the wind; -- usually attached to the lower corner of a sail, or to a yard or a boom.

   2. pl. The space in the forward or the after part of a boat where there are no rowers; as, fore sheets; stern sheets.

      Note: Sheet is often used adjectively, or in combination, to denote that the substance to the name of which it is prefixed is in the form of sheets, or thin plates or leaves; as, sheet brass, or sheet-brass; sheet glass, or sheet-glass; sheet gold, or sheet-gold; sheet iron, or sheet-iron, etc.

      A sheet in the wind, half drunk. [Sailors' Slang]

      Both sheets in the wind, very drunk. [Sailors' Slang]

      In sheets, lying flat or expanded; not folded, or folded but not bound; -- said especially of printed sheets.

      Sheet bend (Naut.), a bend or hitch used for temporarily fastening a rope to the bight of another rope or to an eye.

      Sheet lightning, Sheet piling, etc. See under Lightning, Piling, etc.

Lightning \Light"ning\ (l[imac]t"n[i^]ng), n. [For lightening, fr. lighten to flash.]

1. 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.

2. The act of making bright, or the state of being made bright; enlightenment; brightening, as of the mental powers. [R.]

   Ball lightning, a rare form of lightning sometimes seen as a globe of fire moving from the clouds to the earth.

   Chain lightning, lightning in angular, zigzag, or forked flashes.

   Heat lightning, more or less vivid and extensive flashes of electric light, without thunder, seen near the horizon, esp. at the close of a hot day.

   Lightning arrester (Telegraphy), a device, at the place where a wire enters a building, for preventing injury by lightning to an operator or instrument. It consists of a short circuit to the ground interrupted by a thin nonconductor over which lightning jumps. Called also lightning discharger.

   Lightning bug (Zo["o]l.), a luminous beetle. See Firefly.

   Lightning conductor, a lightning rod.

   Lightning glance, a quick, penetrating glance of a brilliant eye.

   Lightning rod, a metallic rod set up on a building, or on the mast of a vessel, and connected with the earth or water below, for the purpose of protecting the building or vessel from lightning.

   Sheet lightning, a diffused glow of electric light flashing out from the clouds, and illumining their outlines. The appearance is sometimes due to the reflection of light from distant flashes of lightning by the nearer clouds.

n. A broad flash of lightning, with no visible bolt, due to reflection.