Cardboard (French carton, from Italian. Cartone, from carta - paper), folder, varnish (thick, glossy paper, Bristol board, etc.) - the thickest paper, thicker than wrap paper.
There is not a clear boundary between paper and paperboard. According to the Standard (GOST), paper is called "material with a mass per square meter to 250 g, consisting primarily of plant fibers, interconnected by surface adhesion, which may include sizing agents, mineral fillers, chemical and natural fibers, pigments and dyes." Cardboard, in its turn, called as the "material consisting primarily of plant fibers, different from the paper by thickness and weight per square meter." According to the German classification, cardboard is paper with a mass of 1 m? more than 150, most experts believe the cardboard paper thicker than 0.2 mm, or any composite paper.