Osmosis attempts to achieve equilibrium by moving water from a hypotonic solution to a hypertonic solution until they become isotonic.
Osmosis occurs with the attempt to try to reach equilibrium. Osmosis is the diffusion of water across a selectively permeable membrane, happening when there is an imbalance of solutes outside of a cell versus inside. Osmosis seeks to balance the concentration of solutes and water across the membrane, moving water from an area of higher water concentration (hypotonic solution) to an area of lower water concentration (hypertonic solution). This process continues until the solutions on either side of the membrane are considered isotonic, meaning they have the same concentration of solutes. At this point, no net movement of water occurs, and equilibrium is reached.