Emily Dickinson Lexicon

MARSH, n. [Sax. mersc; Fr. marais; D. moeras; G. morast. It was formerly written marish, directly from the French. We have morass from the Teutonic. See Moor.]

A tract of low land, usually or occasionally covered with water, or very wet and miry, and overgrown with coarse grass or with detached clumps of sedge; a fen. It differs from swamp, which is merely moist or spungy land, but often producing valuable crops of grass. Low land occasionally overflowed by the tides, is called salt marsh.