Hint: Hypotonic solution is something related to osmosis. Try to figure out how it is related. In osmosis, hydrostatic pressure is developed on the solution side that just stops the flow of the solvent. Try to identify this pressure.
Complete answer: We know that osmosis occurs in liquid solutions. Osmosis is the process of the spontaneous flow of solvent molecules through a semipermeable membrane from a pure solvent to a solution or from a dilute solution to a concentrated solution. The hydrostatic pressure developed as a result of osmosis is a measure of the osmotic pressure of the solution. The hydrostatic pressure developed on the solution side that is just enough to stop the flow of solvent is osmotic pressure. Osmotic pressure can also be defined as the minimum external pressure which must be applied to the solution to stop the flow of solvent molecules entering into the solution through a semipermeable membrane. The term hypotonic solution is used while comparing the osmotic pressure of two solutions. Let us take two solutions and compare their osmotic pressures. If both the solutions have different osmotic pressures then a solution with lower osmotic pressure is called a hypotonic solution. The hypotonic solution contains a lower concentration of solute so its osmotic pressure will be low.
Note: While comparing osmotic pressures of two solutions if the osmotic pressure of both the solutions is the same then they are called isotonic solutions. A solution with higher osmotic pressure among two solutions is called a hypertonic solution.