Public domain
The opposite of "public domain" is copyrighted material, which is owned either by the creator of the work or their estate.  The term public domain is only used to describe things that can be copyrighted, such as photographs, drawings, written articles, books or plays, or similar works of art.  As a general rule, all intellectual property works, after enough time has gone by, will become part of public domain. Examples include the works of Leonardo da Vinci, William Shakespeare and Ludwig van Beethoven, and the books of Isaac Newton.