Dictionary Definition:

“A process by which molecules of a solvent tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one.”

Selected from OxfordDictionaries.com

Functional Definition:

Osmosis is the movement of particles across a membrane. More specifically it is the movement of water particles from an area of low solute concentration to an area of high solute concentration.

Several terms are used when describing osmosis and the membrane effected my the movement of particles. Hypotonic systems refer to a membrane/cell in which the interior region has a high concentration of solute particles. In this case water/solvent fills the membrane and causes it to burst or become turgid in. Hypertonic is the opposite of hypotonic in which the exterior region has a high concentration of solute particles and water exits the membrane causing it to shrivel. If a region is isotonic then the movement of solute particles and water is balanced and the membrane is neither swollen or shriveled. Plant cells maintain a slightly high hypotonic state allowing them to stay rigid and strong and support the plant’s many organs.