The unauthorized use of a copyrighted work in a manner that violates one of the copyright holder's exclusive rights and does not fall into any of the exceptions to or limitations on the holder's rights.
Example: Copying from a copyrighted work in excess of the maximum allowed
A general rule of thumb is that a student can copy 10% of a work.
The copyright laws of every country include exceptions and limitations to copyright - activities that you can undertake without any fear of violating copyright:
In order to balance the rights of the copyright owner to reasonable compensation with the public's rights to the ideas contained in the copyrighted work, copyright law generally limits the copyright owner's exclusive right by permitting the use of the work without permission and free of charge for certain specified purposes.
In the US it is called fair use.
Fair Use is a doctrine of the United States copyright law that allows limited use of copyrighted works without seeking permission, typically for the purposes of criticism, comment, news reporting, teaching, scholarship, and research. In determining whether or not use of a copyrighted work is fair, the following factors should be considered:
These guidelines provide a minimum standard of educational fair use. The guidelines represent three standards: brevity, spontaneity, and cumulative effect.
I. Single Copy
A single copy of the following may be made for an individual's own scholarly research or in preparation for a class:
II. Multiple Copies for Classroom Use
Multiple copies may be made for classroom use as long as the copies do not exceed more than one copy per person, each copy includes a notice of copyright (e.g., Notice: This material may be protected by copyright law), and the copying meets the definitions of brevity, spontaneity, and cumulative effect, as listed below.
Note: Limitations stated above do not apply to current news periodicals, newspapers, and current news sections of other periodicals.
III. Other Restrictions
IV. Additional Guidelines