sed ‧ i ‧ men ‧ ta ‧ tion /ˌsedəmenˈteɪʃ ə n, ˌsedɪmenˈteɪʃ ə n, -mən-/ BrE AmE noun [uncountable] technical
the natural process by which small pieces of rock, earth etc settle at the bottom of the sea etc and form a solid layer
sed ‧ i ‧ men ‧ ta ‧ tion /ˌsedəmenˈteɪʃ ə n, ˌsedɪmenˈteɪʃ ə n, -mən-/ BrE AmE noun [uncountable] technical
the natural process by which small pieces of rock, earth etc settle at the bottom of the sea etc and form a solid layer
Longman Dictionary of Contemporary English. Longman - Словарь современного английского языка. 2012