What is the difference between diffusion and facilitated diffusion and osmosis

The movement of ions or molecules from an area of higher concentration to lower concentration is known as diffusion. It may or may not take place through a semipermeable membrane. It does not require energy for the movement of molecules.  

A kind of passive transport in which the molecules or ions passes through the semipermeable membrane with the help of permeases located in the membrane. Like simple diffusion, it also does not require energy for the movement of ions or molecules.  

The movement of water from lower concentration to higher concentration via a semipermeable membrane is known as osmosis.