Osmosis is the movement of water molecules from the region of high water potential to low water potential through partially permeable membranes.
High water potential refers to dilute solution however low water potential refers to concentrated solution.
In living cells, the partially permeable membrane is the cell membrane that controls the movement of substances into and out of the cell.
If an animal cell is placed in a dilute solution water moves from outside to inside until the cell bursts.
However if it is placed in concentrated solution water molecules move from inside the cell to outside and the cell becomes shrinked.