Public Domain


The public domain comprises the body of all creative works and other knowledge- writing, artwork, music, science, inventions, and others-in which no person or organization has any proprietary interest. (Proprietary interest is typically represented by a copyright or patent.) Such works and inventions are considered part of the public's cultural heritage, and anyone can use and build upon them without restriction (not taking into account laws concerning safety, export, etc.).

While copyright was designed to promote the development of arts and sciences by giving a (financial) incentive to the creator, works in the public domain just exist as such. The public have the right to use and reuse works in the public domain without financial or social burden. When copyright or other restrictions reach the end of their life, works are said to revert to the public domain.

Absence of legal protection

Creative works are in the public domain wherever no law exists to establish proprietary rights, or where the subject matter is specifically excluded from existing laws. Likewise, works that were created long before such laws were passed are part of the public domain, such as the works of William Shakespeare and Ludwig van Beethoven and the inventions of Archimedes (however, translations of the works of Archimedes, Shakespeare, etc., may be subject to copyright). Also, works of the United States Government are excluded from copyright law.

Non-creative works cannot be copyrighted and are often in the public domain. For example, most mathematical formulas are not subject to copyrights or patents in most of the world (although their application in the form of computer programs can be patented). Facts are in the public domain (although recent legislation has increased copyright-like restrictions on databases that critics claim are only facts). Collections of data with intuitive organization, such as alphabetized directories like telephone directories, are in the public domain. Creative organizations such as categorized lists may be copyrighted.


Most copyrights and patents have a finite term; when this expires, the work or invention is released into public domain. In most of the world, patents expire 20 years after they are filed. Trademarks expire soon after the mark becomes a generic term. Copyrights are more complex; generally, they expire in all countries (except Colombia, Guatemala, Mexico, and Samoa) when all of the following conditions are satisfied:

  • The work was created and first published before January 1, 1923, or at least 95 years before January 1 of the current year, whichever is later.
  • The last surviving author died at least 70 years before January 1 of the current year.
  • No Berne Convention signatory has passed a perpetual copyright on the work.
  • Neither the United States nor the European Union has passed a copyright term extension since these conditions were last updated. (This must be a condition because the exact numbers in the other conditions depend on the state of the law at any given moment .)

These conditions are based on the intersection of United States and European Union copyright law, which most other Berne Convention signatories recognize. Note that copyright term extension under U.S. tradition does not restore copyright to public domain works (hence the 1923 date), but European tradition does because the EU harmonization was based on the copyright term in Germany, which had already been extended to life plus 70. Note further that works created by a United States government agency are public domain at the moment of creation.

British government works are restricted by either Crown Copyright or Parliamentary Copyright. Published Crown Copyright works become public domain at the end of the year 50 years after they were published, unless the author of the work held copyright and assigned it to the Crown. In that case, the copyright term is the usual life of author plus 70 years. Unpublished Crown Copyright documents become public domain at the end of the year 125 years after they were first created. However, under the legislation that created this rule, and abolished the traditional common law perpetual copyright of unpublished works, no unpublished works will become public domain until 50 years after the legislation came into effect. Since the legislation became law on 1 August 1989, no unpublished works will become public domain under this provision until 2039. Parliamentary Copyright documents become public domain at the end of the year 50 years after they were published. Crown Copyright is waived on some government works provided that certain conditions are met.

These numbers reflect the most recent extensions of copyright in the United States and Europe. Canada and Australia have not, as of 2004, passed similar twenty-year extensions. Consequently, their copyright expiry times are still life of the author plus 50 years. As a result, characters such as Mickey Mouse, and works ranging from Peter Pan to the stories of H. P. Lovecraft are public domain in both places. (The copyright status of Lovecraft's work is debatable, as no copyright renewals, which were necessary under the laws of that time, have been found. Also, two competing parties have independently claimed copyright ownership on his work.)

As with most other Commonwealth of Nations countries, Canada and Australia follow the general lead of the United Kingdom on copyright of government works. Both have a version of Crown Copyright which lasts for 50 years from publication. New Zealand also has Crown Copyright, but has a much greater time length of protection at 100 years from the date of publication. Ireland also has a fifty year term on government works, although since it is no longer a monarchy, such a copyright is, of course, not called Crown Copyright. India has a government copyright of sixty years from publication, to coincide with its somewhat unusual life of the author plus sixty years term of copyright.

Examples of inventions whose patents have expired include the inventions of Thomas Edison. Examples of works whose copyrights have expired include the works of Carlo Collodi and most of the works of Mark Twain.

Examples of works under a statutory perpetual copyright include many of the Peter Pan works by J. M. Barrie; this was granted by the British government and applies only within the United Kingdom. Other works, such as the works of The Walt Disney Company are not under a de jure statutory perpetual copyright because the United States Constitution requires copyrights to last "for limited Times" ( Article I, section 8, clause 8). However, the limits have been retroactively extended several times, leading to longer and longer copyright terms. Critics have observed that the extensions have taken place right before noteworthy works from Disney and others were about to expire, concluding that such copyright term extensions add up to de facto perpetual copyright.

Disclaimer of interest

Laws may make some types of works and inventions ineligible for monopoly; such works immediately enter the public domain upon publication. Many kinds of mental creations, such as publicized baseball statistics, are never protected.

For example, U.S. copyright law, 17 U.S.C. § 105, releases all works created by the U.S. government into the public domain, patent applications as part of the terms of granting the patent to the invention are public domain, patent law excludes inventions that obviously follow from prior art, and agreements that Germany signed at the end of World War I released such trademarks as "aspirin" and "heroin" into the public domain in many areas.

Charles Darwin discovered the theory of evolution. This kind of abstract idea has never been patentable. Darwin made the discovery but he did not disclose it for over a decade. He could have kept his manuscript in his desk drawer forever. Once he published the idea, the idea itself entered public domain. However, the carrier of his ideas, in the form of a book titled The Origin of Species, was protected by copyright.


In the past, in some jurisdictions such as the USA, a work would enter the public domain with respect to copyright if it was released without a copyright notice. This is no longer the case. Any work receives copyright by default and copyright law generally doesn't provide any special means to "abandon" copyright so that a work can enter the public domain (in the USA, the Computer Software Rental Amendments Act of 1990 provides a registration mechanism for public domain computer programs at the Library of Congress, but it is still not explained how the work should be placed in the public domain in the first place).

A copyright holder can explicitly disclaim any proprietary interest in the work, effectively granting it to the public domain, by providing a licence to this effect. A suitable licence will grant permission for all of the acts which are restricted by copyright law. Such a license is sometimes called a free use or public-domain equivalent licence.


With regards to patents on the other hand, publishing the details of an invention before applying for a patent will generally place an invention in the public domain and prevent its subsequent patenting by others. For example, once a journal publishes a mathematical formula, it may no longer be used as the core of a claim in a software patent. There is an exception to this, however: in U.S. (not European) law, an inventor may file a patent claim up to one year after publishing it (but not, of course, if someone else published it first).

Another way to disclaim parts of an invention is by the doctrine of prosecution history estoppel. When a patent application is being prosecuted by the patent examiner, the applicant may abandon certain claims in exchange of approval. At least in theory, the applicant may unilaterally abandon nearly all patent claims and receive an empty patent. If the patentee sues anyone over patent infringement, during claim construction, the prosecution history will be used to define the scope of the patent claims.

Trade secret

If guarded properly, trade secrets are forever. A business owner may keep The Answer to Life, the Universe, and Everything a secret. However, once it is disclosed to the public, the secret enters public domain.


A trademark is renewable. If a trademark owner wish to continue his/her business, he/she can pay the registration fees and used and defended the trademark actively forever.

However, a trademark or brand name can become a generic term of a particular type of product or service if people use it this way so they don't realize it is a trademark. One famous example is "aspirin" in the United States.

Once a trademark becomes genericized, it is like in the public domain. Anyone is allowed to label a bottle of 2-acetoxybenzoic acid pills "aspirin" in the United States.

Domain name

People may buy and sell domain names. Sometimes, people advertise them as their own "intellectual property". In early 2000, the record-breaker domain name "" was sold for $8 million. At the time, people were grabbing domain names like crazy.

A domain name never enters public domain. It is very likely that it does not belong to its "owner". Top level domains, such as .com, are owned by the ICANN (Internet Corporation for Assigned Names and Numbers). An "owner" leased has exclusive rights to a domain name for a limited period of time, which can be considered in the same way as lease of real estate. Therefore, if the "owner" later "abandons" the domain name, the unused domain name itself is still owned by the ICANN.

The domain name "" either directs to a website or it is unused or unregistered. It can be used by some people, it cannot be used by all people.


Note that there are many works that are not part of the public domain, but for which the owner of some proprietary rights has chosen not to enforce those rights, or to grant some subset of those rights to the public. See, for example, the Free Software Foundation which creates copyrighted software and licenses it without charge to the public for most uses under a class of license called "copyleft", forbidding only proprietary redistribution. Wikipedia does much the same thing with its content under the GNU Free Documentation License. Sometimes such work is mistakenly referred to as "public domain" in colloquial speech.

Note also that while some works (especially musical works) may be in the public domain, U.S. law considers transcriptions or performances of those works to be derivative works, potentially subject to their own copyrights.

The role in society

Creative Commons, an organization that promotes use of the public domain and copyleft licensing schemes, writes:

"Public access to literature, art, music, and film is essential to preserving and building on our cultural heritage. Many of the most important works of American culture have drawn upon the creative potential of the public domain. Frank Capra's It's a Wonderful Life is a classic example of a film that did not enjoy popular success until it entered the public domain. Other icons such as Snow White, Pinocchio, Santa Claus and Uncle Sam grew out of public domain figures."

Public domain and the Internet

The term "public domain" is often poorly understood and has created significant legal controversy. Historically, most parties attempting to address public domain issues fell into two camps:

  1. Businesses and organizations who could devote staff to resolving legal conflicts through negotiation and the court system.
  2. Individuals and organizations using materials covered by the fair use doctrine, reducing the need for substantial governmental or corporate resources to track down individual offenders.

With the advent of the Internet, however, it became possible for anybody with access to this worldwide network to "post" copyrighted or otherwise-licensed materials freely and easily. This aggravated an already established but false belief that, if something is available through a free source, it must be public domain. Once such material was available on the net, it could be perfectly copied among thousands or even millions of computers very quickly and essentially without cost.

These factors have reinforced the false notion that "freely obtained" means "public domain". One could argue that the Internet is a publicly-available domain, not licensed or controlled by any individual, company, or government; therefore, everything on the Internet is public domain. This specious argument ignores the fact that licensing rights are not dependent on the means of distribution or consumer acquisition. (If someone gives you stolen merchandise, it is still stolen, even if you weren't aware of it.) Chasing down copyright violations based on the erroneous idea that "information is free" (see Footnotes below) has become a primary focus of industries whose financial structure is based on their control of the distribution of such media. Though this is legally correct, public support for these companies' efforts is significantly undermined by the belief that they are receiving their "just desserts" for decades of price-gouging for licensed media. Ironically, this puts many creators of such work, like musicians and authors, on both sides of the issue, since they have frequently fought media distributors over inadequate compensation for their work, but depend on distributors' revenues for that compensation.

Another complication is that publishing exclusively on the Internet has become extremely popular. According to U.S. law, at least, an author's original works are covered by copyright, even without a formal notice incorporated into the work. But such laws were passed at a time when the focus was on materials that could not be as easily and cheaply reproduced as digital media, nor did they comprehend the ultimate impossibility of determining which set of electronic bits is original. Technically, any Internet posting (such as blogs or emails) could be considered copyrighted material unless explicitly stated otherwise. (Many Internet content providers attempt to assert copyrights by claiming all ownership and reproduction rights to any material posted to their servers, but the potential for conflicting claims has not been adequately tested.) Traditional methods of proving original work, such as physically mailing a sealed copy of one's work to oneself, thereby gaining a dated stamp from a governmental agency (i.e., the local Postal Service), are irrelevant for this new source of creative work.

Many people are using the Internet to contribute to the public domain, or make works in the public domain more accessible to more people. For example, Project Gutenberg is coordinating the efforts of people who transcribe works in the public domain into electronic form.


  1. In response to the frequently-championed concept that "information is free", technology columnist Nicholas Petreley once wrote, "Those who want information to be free as a matter of principle should create some information and make it free." This statement concisely illustrates the conflict between the cultural desire to make original material readily and cheaply (or freely) available and the right of original-work creators to receive compensation for their work.

Wikipedia article (the free online encyclopedia) reproduced under the terms of the GNU (General Public License) Free Documentation License.

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