Poly-viscose tartan (or just poly viscose) is a blend of viscose and polyester. Blending polyester with viscose gives the best of both worlds, very affordably. Poly viscose is best described as a semi-natural or semi-synthetic fibre. A pattern made of intersecting stripes, originally made from wool with a twill weave. Each tartan pattern is associated with a certain specific family called a clan. Plaid, a term used for tartan, is actually the name of a shawl made of tartan fabric.  The use of plaid has become so general that tartan is almost always limited to authentic clan designs.