Silt, silt or silt is an incoherent clastic sediment transported in suspension by rivers and by the wind, which is deposited on the bed of water courses or on land that has been flooded.[1]​[2]​ To be classified as such, the diameter of the "Grain (mineral)") particles of silt must be between 0.0039 mm and 0.0625 mm.

Typical is the silt deposited by the Nile River in the territories adjacent to it after floods that provided fertile land for agriculture, which had been used since ancient Egypt, until this flow was interrupted by the construction of the Aswan Dam in the 2nd century.

Since it does not have cohesion "Cohesion (strength)"), it is a problematic terrain to build on, and in architectural or engineering works, it is necessary to adopt special foundation systems.

Within the granulometric classification of soil particles, silt occupies the following place in the ranking: