洪積層
Diluvium \Di*lu"vi*um\, n.; pl. E. {Diluviums}, L. {Diluvia}. [L. diluvium. See {Dilute}, {Deluge}.] (Geol.) A deposit of superficial loam, sand, gravel, stones, etc., caused by former action of flowing waters, or the melting of glacial ice. Note: The accumulation of matter by the ordinary operation of water is termed alluvium.