Inside the container we have some water molecules and inside those water molecules we have some sugar molecules. We have more water molecules so in this case the thing which is more of called SOLVENT and the thing which is lesser is called SOLUTE. We can say sugar molecule dissolves in the water. The combination of Solvent and Solute is called the SOLUTION. Diffusion is spreading the molecules from high concentration to low concentration. If we take two containers of water which are joined from the middle. We add some sugar molecules in left container. It moves from high concentration to low concentration. This is also diffusion where molecules move from Hyper tonic concentration to hypo tonic concentration. water can go in and outside of the Membrane but sugar molecules inside the membrane can't come outside the membrane. Sugar is Solute water is Solvent. Water enters inside the membrane. This idea of water as a solvent diffusing to the semi permeable membrane is called Osmosis. There is a membrane so actual solute cannot travel.