The Collaborative International Dictionary of English v.0.48:

Silt \Silt\ (s[i^]lt), 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[imac]gan to fall, sink, cause to
   sink, G. seihen to strain, to filter, OHG. s[imac]han, Icel.
   s[imac]a, Skr. sic to pour; cf. Gr. 'ikma`s moisture. Cf.
   Sig, Sile.]
   Mud or fine earth deposited from running or standing water.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Silt \Silt\, v. t. [imp. & p. p. Silted; p. pr. & vb. n.
   Silting.]
   To choke, fill, or obstruct with silt or mud.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Silt \Silt\, v. i.
   To flow through crevices; to percolate.
   [1913 Webster]

WordNet (r) 3.0 (2006):

silt
    n 1: mud or clay or small rocks deposited by a river or lake
    v 1: become chocked with silt; "The river silted up" [syn: silt
         up, silt]