According to the Copyright office at the Library of Congress, copyright infringement "occurs when a copyrighted work is reproduced, distributed, performed, publicly displayed, or made into a derivative work without the permission of the copyright owner." (http://www.copyright.gov/help/faq/faq-definitions.html)

While the term "theft" is not strictly applied to the act of infringing the rights of a copyright owner, "piracy" has been applied to copyright infringement since the Renaissance. Piracy traditionally refers to any act violating the intellectual property rights of a copyright owner with the goal of financial gain. More recently, the definition of this term has been broadened to include any unsanctioned copying for any motivation, financial or not.  (http://arstechnica.com/tech-policy/news/2012/04/raskally-fellows-are-copyright-infringers-pirates-and-thieves.ars/1)