👉 Permeability refers to a property of materials that allows or prevents water from passing through them. It is defined as the ability of a material to resist or absorb the movement of water, whether it be through evaporation, condensation, or other processes. Permeability can vary depending on the type of material and its composition, but generally, permeable materials are more likely to allow water to pass through than non-permeable materials such as glass or plastic.