Definitions

from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. A form of licensing that encourages the distribution of software at no charge for noncommercial uses.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. The philosophy of using copyrights to enforce freedom of information, especially software source code.
  • n. A software license that follows this philosophy.
  • v. To license under a copyleft license.

Etymologies

After copyright.
(American Heritage® Dictionary of the English Language, Fourth Edition)
Pun on copyright. (Wiktionary)

Examples

  • The Copyleft Foundation, which initiates its course this coming month of October year 2006, issues a formal invitation to participate to all those interested in copyleft and who form a part of the chain of assessment of the arts, culture an science as well as individuals and associative companies.

    Boing Boing

  • The GPL is called a copyleft license, which is wordplay on copyright.

    Linux Today

  • A concept in competition with the idea of copyleft is the "non-commercial" license, which attempts to restrict the use of a work for "commercial" purposes.

    LXer Linux News

  • "copyleft" - software licenses that not only allow copying, but require it.

    Netvouz - new bookmarks

  • It is radical because previous attempts have tried to build on the evident success of the GNU GPL by taking a kind of copyleft approach: using copyright to limit copyright.

    Open Access Data - A Question of Protocol

  • Do you own the copyright, and if so would you be willing to give a general "copyleft" or other no-royalty license?

    Constitutional curiosities: a 21-question scavenger hunt

  • IP practitioners frequently complain about the academythe "copyleft" as they are found sic of saying.

    Scrivener's Error

  • This License is a kind of "copyleft," which means that derivative works of the document must themselves be free in the same sense.

    How To Think Like a Computer Scientist, Learning with Python

  • This approach, known as "copyleft", as opposed to copyright, languished in obscurity until the internet made it easier for far-flung groups of developers to collaborate-which led to an explosion of open-source activity.

    The Economist: Correspondent's diary

  • As a musician, and as an entrepreneur making my living selling equipment to studios and musicians, I obviously have a great deal to lose if the putative forces of "copyleft" somehow succeed in preventing music being paid for.

    Techdirt

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Comments

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  • I can also see them both now

    May 15, 2009

  • I can see both of them here from a different computer, same Firefox, but using Linux this time.

    May 15, 2009

  • How about ?

    May 15, 2009

  • Me neither

    May 15, 2009

  • I can't see it.

    May 15, 2009

  • Can you see a reversed c here? → Ↄ

    I got it from here, but I can't view it on my machine.

    There's been some discussion about the possibility of adding the symbol here.

    May 11, 2009

  • Does the copyleft symbol exist as a font? Is there any right-left equivalent of the upside-down tool whichbe linked to on upside-down?

    May 11, 2009

  • Often used to describe the GPL, the GNU Public License.

    January 8, 2008