 | This page in a nutshell: Wikipedia content is under a "free" (libre) license and may be re-distributed by anyone, including commercial entities. The licensing terms of Wikipedia do not require publishers or vendors to supply Wikipedia content "free" (gratis) of charge. |
Wikipedia is a part of the Wikimedia Foundation, a non-profit charitable organisation whose mission it is "to empower and engage people around the world to collect and develop educational content under a free license or in the public domain, and to disseminate it effectively and globally."
To serve this end, all Wikipedia content is licensed under "free" (libre) copyright licenses. Similar licenses in the domain of computer software are described as being, "a matter of liberty, not price. To understand the concept, you should think of 'free' as in 'free speech', not as in 'free beer'." Wikipedia articles may be freely copied and sold commercially so long as publishers adhere to the terms of the copyright license under which the content is made available.
Publishers are allowed to sell copies of Wikipedia, and consumers, if they so choose, are allowed to pay for what they could get at no charge through the Wikimedia Foundation's websites.
For more information, see Wikipedia:Copyright.