Porous material is a type of material that has tiny holes or pores in it, allowing liquids and gases to pass through. The term 'porous material' can refer to a variety of materials, such as paper, cloth, and even some types of rocks. In this crossword, the solution for the term 'porous material' is 'FILTER, ' which is an object made of porous material that is used to separate particles from a liquid or gas. Filters are often used in water treatment systems, air purification systems, and other applications.