Final answer:
Isotonic is the state of osmosis in which the concentration of water is the same on both sides.
Step-by-step explanation:
Osmosis is the diffusion of water molecules across a selectively permeable membrane from an area of higher concentration to an area of lower concentration. In the context of osmosis, a state in which the concentration of water is the same on both sides of a membrane is called isotonic. This means that the amount of water entering the cell is the same as the amount leaving the cell.