silt

Silt comes from Middle English silte or cilte, possibly related to the verb silen, meaning to filter or strain. It may also be cognate with Norwegian and Danish sylt ("salt marsh") and Middle Low German sulte ("salt-marsh"), tracing back to Proto-Germanic *sultijō, meaning salty water or brine.

The word likely started as a term tied either to straining or filtering, or to salt marshes and brine, before settling into its modern sense of fine river-deposited sediment.

It's connected to Old English sealt, the ancestor of our word "salt," through the shared Proto-Germanic root *sultijō.