What is the process called that describes the movement of water from a higher to a lower concentration across a selectively permeable membrane?

The process described is osmosis, which specifically refers to the movement of water molecules through a selectively permeable membrane from an area of higher water concentration (or lower solute concentration) to an area of lower water concentration (or higher solute concentration). This movement occurs until equilibrium is reached, meaning that water concentrations on both sides of the membrane become equal.

Osmosis is crucial for maintaining cell turgor and fluid balance within organisms. The selectively permeable nature of the membrane allows water to move freely while restricting the passage of solutes, thereby facilitating this specific form of transport.

While diffusion involves the movement of solutes from high to low concentration, osmosis is unique because it specifically pertains to water movement. Filtration refers to the movement of water and solutes through a membrane due to hydrostatic pressure, which differs from the concentration gradient driving osmosis. Passive transport is a broader category that encompasses processes like diffusion and osmosis, but osmosis is specifically defined by the movement of water, making it the precise term for this question.