Like some markers can refer to three different things. FELT is a type of material made from fibers of animal fur or synthetic fibers that are pressed and matted together. It is often used for crafts, clothing, and furniture. GENETIC markers are specific DNA sequences that are used to identify individuals or species. They are used in GENETIC research and testing. PERMANENT markers are markers that are designed to write on surfaces that are difficult to erase. They are often used for labeling and writing on non-porous surfaces.