silt (n.)

Old English up, uppe, from Proto-Germanic *upp- "up" (source also of Old Frisian, Old Saxon up "up, upward," Old Norse upp; Danish, Dutch op; Old High German uf, German auf "up"; Gothic iup "up, upward," uf "on, upon, under;" Old High German oba, German ob "over, above, on, upon"), from PIE root *upo "under," also "up from under," hence also "over."

As a preposition, "to a higher place" from c. 1500; also "along, through" (1510s), "toward" (1590s). Often used elliptically for go up, come up, rise up, etc. Up the river "in jail" first recorded 1891, originally in reference to Sing Sing, which is up the Hudson from New York City. To drive someone up the wall (1951) is from the notion of the behavior of lunatics or caged animals. Insulting retort up yours (scil. ass) is attested by late 19c.

Proto-Indo-European root meaning "salt."

It forms all or part of: hali-; halide; halieutic; halite; halo-; halogen; sal; salad; salami; salary; saline; salmagundi; salsa; salsify; salt; salt-cellar; saltpeter; sauce; sausage; silt; souse.

It is the hypothetical source of/evidence for its existence is provided by: Greek hals "salt, sea;" Latin sal, Old Church Slavonic soli, Old Irish salann, Welsh halen, Old English sealt, German Salz "salt."