What does silt mean?
Silt is the fine sediment deposited by flowing water, especially in rivers, deltas, and reservoirs. In everyday use, the word often suggests the muddy material left behind after floods or as rivers gradually slow down. Silt can be useful: regular flooding historically renewed fertile soils, although in other places it buries crops, damages infrastructure, or obstructs waterways. As a verb, “silt” means to become filled or blocked with fine sediment, as in “the harbor silts up.” The term is also used in geology and civil engineering for fine material that settles out of suspension in water. Although silt and sediment overlap, silt specifically emphasizes the fine texture of the deposited material.
Fine sediment, especially mud or soil, deposited by flowing water.
"A layer of silt covered the fields after the flood."
Usually treated as a mass noun; it does not normally take a plural.
To become filled or obstructed with fine sediment.
"The inlet gradually silted up with sand and mud."
Most often used intransitively in the phrase “silt up.”
Normally a mass noun and does not take a plural form.
"The flood deposited silt along the riverbank."
The Nile's famous fertility came with a cost: its yearly flood also deposited layers of silt that could bury fields, homes, and entire villages.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does silt come from?
The English word “silt” comes from Old English silte, meaning fine mud or sediment. It is cognate with words in several Germanic languages, including Dutch slib and German Schlick, referring to fine wet earth or mud. In English, its meaning gradually broadened from the material itself to the process or condition of filling a waterway with deposited sediment.
Related word forms
How silt is actually used
Silt is a mass noun and is normally used without a plural. In technical usage, it refers specifically to sediment composed mainly of very fine particles.
Easily confused with silt
Silt is a fine-grained type of sediment deposited by water, whereas sediment is the broader term for particles that settle from water, air, or other materials.