Osmosis is the scientific process of movement of a solvent through a selectively permeable membrane. (“Selectively permeable” basically means that some things can pass through, while others cannot.) If that sounds a little too dense, you can think of osmosis as the movement of water between cells. Basically, if there is a high concentration of molecules (salt, for example) in a cell, other cells will naturally inject more water into the first cell, so that all of them have an even concentration of salts. The movement of water helps to improve stability and function of our cells, and it occurs naturally in all plants and animals.
Osmosis water uses the principle of “reverse osmosis.” Basically, this is a purification process that pushes water though a membrane. Using pressure, water can be forced back through a membrane, removing molecules and resulting in extremely low concentrations of impurities. So osmosis is the process of water flowing to where the molecules are, while reverse osmosis is the process of using pressure to push water away from molecules; thereby purifying the water.