1547, from Fr. sédiment (16c.), from L. sedimentum "a settling, sinking down," from stem of sedere "to settle, sit" (see sedentary). As a type of rock, sedimentary is first recorded 1830 (in Lyell); sedimentation is from 1874.
Geology Solid fragmented material, such as silt, sand, gravel, chemical precipitates, and fossil fragments, that is transported and deposited by water, ice, or wind or that accumulates through chemical precipitation or secretion by organisms, and that forms layers on the Earth's surface. Sedimentary rocks consist of consolidated sediment.
Particles of solid matter that settle out of a suspension to the bottom of the liquid.