means A broad, thin, flat piece of something — cloth, paper, metal, ice, or water — large in its surface but slight in its thickness.

from From Old English 'scēte' (a cloth) and the related 'scēat' (a corner or cloth), both traced back to a Proto-Germanic root meaning to project or shoot out — a cousin of the 'sheet' of a sail and even of the verb 'shoot.' The thread connecting them is the idea of something flung wide and stretched flat, whether across a bed or against the wind.