Source : Webster's Revised Unabridged Dictionary (1913)

Silt \Silt\, n. [OE. silte gravel, fr. silen to drain, E. sile;
   probably of Scand. origin; cf. Sw. sila, prob. akin to AS.
   se['o]n to filter, s[=i]gan to fall, sink, cause to sink, G.
   seihen to strain, to filter, OHG. sihan, Icel. s[=i]>a, Skr.
   sic to pour; cf. Gr. ??? moisture. Cf. {Sig}, {Sile}.]
   Mud or fine earth deposited from running or standing water.

Silt \Silt\, v. t. [imp. & p. p. {Silted}; p. pr. & vb. n.
   {Silting}.]
   To choke, fill, or obstruct with silt or mud.

Silt \Silt\, v. i.
   To flow through crevices; to percolate.

Source : WordNet®

silt
     n : mud or clay or small rocks deposited by a river or lake

silt
     v : become chocked with silt; "The river silted up" [syn: {silt
         up}]