My textbook says this:
Osmosis is the diffusion of water.
Wikipedia says this:
The diffusion model of osmosis is rendered untenable by the fact that osmosis can drive water across a membrane toward a higher concentration of water.
It's my understanding that diffusion is passive transport, and it moves material from a highly concentrated area of that material to an area where it is in lower concentration. By this definition, it looks like Wikipedia is correct. But if for example, a cell is put in saltwater, water from within the cell would go out. Is this diffusion now? Which definition is correct?
I would just go with the Wikipedia definition because it actively describes its own definition as a refinement of the textbook definition, but the paragraph above in the article is a bit confusing to me.