Fair use is a provision of the copyright law which limits the rights of the copyright holder. It allows individuals to use copyrighted works "for purposes such as criticism, comment, news reporting, teaching (including multiple copies for classroom use), scholarship, or research."
Four factors must be analyzed in determining whether or not the intended use of a copyrighted item falls under fair use:
the purpose and character of the use, including whether such use is of a commercial nature or is for nonprofit educational purposes;
the nature of the copyrighted work;
the amount and substantiality of the portion used in relation to the copyrighted work as a whole; and
the effect of the use upon the potential market for or value of the copyrighted work.
Source: 17 U.S.C. § 107
Fair use is a balancing act, weighing the aforementioned four factors on a case by case basis.
The fair use checklist is a helpful tool in making a fair use analysis. The checklist should be completed for each use.