sed·i·ment 
/ˈsɛdəmənt/ noun
plural sed·i·ments /ˈsɛdəmənt/ noun [count, noncount] 1 : material that sinks to the bottom of a liquid
▪ There was a layer of sediment in the bottom of the tank. 2 : material (such as stones and sand) that is carried into water by water, wind, etc.
▪ There was a layer of sediment in the bottom of the tank.
