Oriented strand board (OSB) is a type of engineered wood similar to particle board, formed by adding adhesives and then compressing layers of wood strands (flakes) in specific orientations. It was invented by Armin Elmendorf in California in 1963. OSB may have a rough and variegated surface with the individual strips of around , lying unevenly across each other, and is produced in a variety of types and thicknesses. Though it may seem intuitive to assume that the term "chipboard" refers to oriented strand board based on its appearance, and to contrast it against particle board, the two terms are treated as synonyms by the industry, with the "chips" in chipboard being of a size that a lay person would readily judge to be "particles".
