What do you mean by porosity?

Porosity refers to the measure of empty spaces or voids within a material, such as soil, rock, or concrete. It is expressed as a percentage of the total volume that is made up of these voids. High porosity indicates that a material can hold a significant amount of fluid, while low porosity suggests limited capacity for fluid retention. This property is crucial in fields like geology, hydrology, and civil engineering, as it affects water movement and storage.