Public Domain
What does "Public Domain" mean in law?
The public domain consists of creative works and inventions that are not protected by intellectual property laws and are therefore freely available for anyone to use without permission or payment. Works enter the public domain through several pathways: copyright expiration (life of the author plus 70 years, or 95 years from publication for works for hire), failure to comply with former formalities such as copyright notice or renewal, explicit dedication by the rights holder, or because the work is inherently ineligible for protection (such as U.S. government works under 17 U.S.C. section 105, or unoriginal facts and ideas). Once a work enters the public domain, it cannot be reclaimed by copyright, and anyone may reproduce, adapt, or distribute it.
Definition
The public domain consists of creative works and inventions that are not protected by intellectual property laws and are therefore freely available for anyone to use without permission or payment. Works enter the public domain through several pathways: copyright expiration (life of the author plus 70 years, or 95 years from publication for works for hire), failure to comply with former formalities such as copyright notice or renewal, explicit dedication by the rights holder, or because the work is inherently ineligible for protection (such as U.S. government works under 17 U.S.C. section 105, or unoriginal facts and ideas). Once a work enters the public domain, it cannot be reclaimed by copyright, and anyone may reproduce, adapt, or distribute it.
Example
Shakespeare's plays are in the public domain, meaning any publisher can print them, any theater company can perform them, and any filmmaker can adapt them into a movie without obtaining permission or paying royalties.