Paper has traditionally been defined as a felted sheet formed on a fine screen from a water suspension of fibers.  Current paper products generally conform to this definition except that most products also contain non-fibrous additives.  Dry forming methods are now used for the manufacture of a few specialty paper products.

Pulp is the fibrous raw material for papermaking.  Pulp fibers are usually of vegetable origin, but animal, mineral, or synthetic fibers may be used for special applications.  Pulps used for chemical conversion into non-paper products are called dissolved pulp.

Paper and paperboard are very similar.  The distinction between paper and paperboard is based on product thickness.  All sheets above 0.3 mm thickness are classified as paperboard although exceptions are applied making the distinction somewhat hazy.