Alluvial

Part of speech: adjective

Pronunciation: /əˈluː.vi.əl/

Definitions

1. Relating to fine sediment deposits such as silt, clay, and sand that are carried and left by flowing water in river valleys and floodplains
2. Pertaining to sediment materials including sand, silt, and clay that are transported and deposited by moving water in low-lying areas
3. Of or composed by sediment particles carried by running water and deposited in valleys or plains
4. pertaining to sediment materials like silt, sand, and clay transported and deposited by rivers and streams
5. of or composed of fine particles such as clay, silt, and sand that accumulate through water erosion and deposition in valleys

Etymology: "Alluvial" describes soil, sand and silt that rivers have carried and dropped, often forming fertile plains and deltas. The word comes from Latin "alluvius," meaning "washed against" or "overflowing," built on "alluō," "wash against." The Latin noun "alluvio" meant an inundation, a flood that spreads over land, so the word began as a description of water rather than of the mud it left behind. The English form is "alluvium," a noun for those deposits, with the adjective "alluvial" made by adding "-ial," the usual adjective ending, to it. So the adjective is one step removed from the flood itself: the water washes against the land, and the land keeps what the water brought.

Synonyms: fluvial, riverine, sedimentary