👉 Porosity, a property of materials that refers to their capacity for water absorption and excretion. It is a measure of how much air can permeate through a material without being absorbed or retained by it. In other words, porosity is a measure of how well a material retains moisture, and the greater the porosity, the more easily water can be absorbed into the material. Porosity can also affect materials' thermal conductivity, electrical conductivity, and chemical reactions, among others.