The process of settling down of a heavy, insoluble solid is called decantation.
Definition for decantation
Decantation is the process of pouring out of the liquid into another container to separate two immiscible liquids. Example- Separation of oil and water.
Definition of sedimentation.
Settle down of heavier insoluble particles/solids from a mixture is called sedimentation. Example- Water with mud.
Therefore the given statement is false.