mid-15c., originally "sediment deposited by seawater," probably from a Scandinavian source (cf. Norwegian and Danish sylt "salt marsh"), or from Middle Low German or Middle Dutch silte, sulte "salt marsh, brine," from Proto-Germanic *sultjo- (cf. Old English sealt, Old High German sulza "saltwater," German Sulze "brine"), from PIE *sal- (see salt (n.)).
A sedimentary material consisting of grains or particles of disintegrated rock, smaller than sand and larger than clay. The diameter of the particles ranges from 0.0039 to 0.0625 mm. Silt is often found at the bottom of bodies of water where it accumulates slowly by settling through the water.