Osmosis is the diffusion of water from a dilute solution to a concentrated solution across a partially permeable membrane.
Terms: Diffusion (the net movement of particles from a high to a low concentration.)
Both of these explanations are ones that it is important to learn by heart and understand in order to build on your knowledge. Doing past papers and looking closely at mark schemes allows you to identify key buzz words. For osmosis - diffusion, water, partially permeable membrane and the idea of moving from dilute to concentrated will get you all the marks.