Dictionary.net

Tendency of fluids (e.g., water) to move from the less concentrated to the more concentrated side of a semipermeable membrane.

Liquids impelled through moist membranes.

A diffusion which takes place between two miscible fluids through a permeable membrane.

The passage of a fluid through a membrane.

The passage of water through a porous septum, in consequence of a difference in osmotic pressure or concentration of the dissolved substances. The osmotic pressure of any solution is dependent upon the number of particles (molecules and ions) in solution and, mechanically measured, it is equal to the gas pressure exerted by the same number of gas molecules in the same volume. [Gr.]