What are paper grades and basis weights and there common uses?

Paper grades are defined by their usage, such as Book or Cover stock. They are often referred to in combination with a basis weight: for example, 20 lb. Bond or 70 lb. Book. Another abbreviation for pound is #. Most copy paper that you would find at an office supply store (in the U.S.) is 20 lb bond with a brightness rating of 92-96.