And hypertonic solutions:

Hypotonic solution: A hypotonic solution is a solution in which the concentration of solutes is lower than that of the cell or solution. When a cell is placed in a hypotonic solution, water flows into the cell causing it to swell and potentially burst.

Isotonic solution: An isotonic solution is a solution in which the concentration of solutes is equal to that of the cell or solution. When a cell is placed in an isotonic solution, there is no net movement of water into or out of the cell.

Hypertonic solution: A hypertonic solution is a solution in which the concentration of solutes is higher than that of the cell or solution. When a cell is placed in a hypertonic solution, water flows out of the cell causing it to shrink or shrivel.

In hypotonic solution water outside the cell is more so the cell gains water by osmosis.In isotonic solution water inside the cell and outside the cell is equal so there is no movement of water.In hypertonic solution water inside the cell is less than outside the cell so the cell will lose the water by osmosis.