The measure of the relative tendency of water to move from one area to another, and is commonly represented by the Greek letter Ψ (Psi).
Water potential is caused by osmosis, gravity, mechanical pressure, or matrix effects including surface tension. It is useful in understanding water movements within plants, animals, and soil.
Word origin: potential » Late Latin potentiālis, powerful, from Latin potentia, power.
Compare: Osmotic Potential.
See also: osmosis.