A signature (from Latin: signare, "to sign") is a handwritten (and often stylized) depiction of someone's name, nickname, or even a simple "X" or other mark that a person writes on documents as a proof of identity and intent. The writer of a signature is a signatory or signer. Similar to a handwritten signature, a signature work describes the work as readily identifying its creator. A signature may be confused with an autograph, which is chiefly an artistic signature. This can lead to confusion when people have both an autograph and signature and as such some people in the public eye keep their signatures private whilst fully publishing their autograph.
Function and types of signatures 
The traditional function of a signature is evidential: it is to give evidence of:
- The provenance of the document (identity)
- The intention (will) of an individual with regard to that document
For example, the role of a signature in many consumer contracts is not solely to provide evidence of the identity of the contracting party, but also to provide evidence of deliberation and informed consent.
In many countries, signatures may be witnessed and recorded in the presence of a notary public to carry additional legal force. On legal documents, an illiterate signatory can make a "mark" (often an "X" but occasionally a personalized symbol), so long as the document is countersigned by a literate witness. In some countries, illiterate people place a thumbprint on legal documents in lieu of a written signature.
There are many other terms which are synonymous with 'signature'. In the United States, one is John Hancock, named after the first of the signatories of the United States Declaration of Independence.
The signature of a famous person is sometimes known as an autograph, and is then typically written on its own or with a brief note to the recipient. Rather than providing authentication for a document, the autograph is given as a souvenir which acknowledges the recipient's access to the autographer.
In the United States, signatures encompass marks and actions of all sorts that are indicative of identity and intent. The legal rule is that unless a statute specifically prescribes a particular method of making a signature it may be made in any number of ways. These include by a mechanical or rubber stamp facsimile. A signature may be made by the purported signatory; alternatively someone else duly authorized by the signatory, acting in the signer's presence and at the signatory's direction, may make the signature.
Many individuals have much more fanciful signatures than their normal cursive writing, including elaborate ascenders, descenders and exotic flourishes, much as one would find in calligraphic writing. As an example, the final "k" in John Hancock's famous signature on the US Declaration of Independence loops back to underline his name. This kind of flourish is also known as a paraph.
Several cultures whose languages use writing systems other than alphabets do not share the Western notion of signatures per se: the "signing" of one's name results in a written product no different from the result of "writing" one's name in the standard way. For these languages, to write or to sign involves the same written characters. Also see Calligraphy.
Mechanically produced signatures 
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Special signature machines, called autopens, are capable of automatically reproducing an individual's signature. These are typically used by people required to sign a lot of printed matter, such as celebrities, heads of state or CEOs.
More recently, Members of Congress in the United States have begun having their signature made into a TrueType font file. This allows staff members in the Congressman's office to easily reproduce it on correspondence, legislation, and official documents.
Online usage 
In e-mail and newsgroup usage, another type of signature exists which is independent of one's language. Users can set one or more lines of custom text known as a signature block to be automatically appended to their messages. This text usually includes a name, contact information, and sometimes quotations and ASCII art. A shortened form of a signature block, only including one's name, often with some distinguishing prefix, can be used to simply indicate the end of a post or response. Some web sites also allow graphics to be used. Note, however, that this type of signature is not related to electronic signatures or digital signatures, which are more technical in nature and not directly understandable by humans.
Other uses 
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The signature on a painting or other work of art has always been an important item in the assessment of art. Fake signatures are sometimes added to enhance the value of a painting, or are added to a fake painting to support its authenticity. A notorious case was the signature of Johannes Vermeer on the fake "Supper at Emmaus" made by the art-forger Han van Meegeren.
However, that oftentimes painters' signatures vary over time (particularly in the modern and contemporary periods) might complicate the issue. The signatures of some painters take on an artistic form that may be of less value in determining forgeries. For example, Daniel C. Boyer's gouaches are known for their often large, elaborate to the point of near-illegibility and multicoloured signatures.
The term "signature" is also used to mean the characteristics that give an object, or a piece of information, its identity—for example, the shape of a Coca-Cola bottle.
By analogy, the word "signature" may be used to refer to the characteristic expression of a process or thing. For example, the climate phenomenon known as ENSO or El Niño has characteristic modes in different ocean basins which are often referred to as the "signature" of ENSO.
Under United States Copyright Law, "titles, names [...]; mere variations of typographic ornamentation, lettering, or coloring" are not eligible for copyright; however, the appearance of signatures (not the names themselves) may be protected under copyright law. It has been deemed illegal to publish signatures[clarification needed] in Canada.
Uniform Commercial Code 
Uniform Commercial Code §1-201(37) of the United States generally defines signed as "using any symbol executed or adopted with present intention to adopt or accept a writing."
Uniform Commercial Code §3-401(b) for negotiable instruments states "A signature may be made (i) manually or by means of a device or machine, and (ii) by the use of any name, including a trade or assumed name, or by a word, mark, or symbol executed or adopted by a person with present intention to authenticate a writing."
See also 
|Look up signature in Wiktionary, the free dictionary.|
- Autograph club
- Biometric signature as form of the Electronic signature
- Cryptographic (digital) signature using Public key infrastructure
- Diabolical signature, said to identify the demons in diabolical pacts
- Images of signatures
- manu propria (m.p.)
- Mobile Signature
- Royal sign-manual
- Signature (wealth manager)
- Signature move
- Oxford English Dictionary, accessed May 3, 2011.
- 80 Corpus Juris Secundum, Signatures, sections 2 through 7
- paraphe is a term meaning flourish, initial or signature in French. French to English translation by CollinsDictionary.com. Collins French-English Dictionary - Complete & Unabridged 11th Edition. Retrieved November 09, 2012.
- The paraph is used in graphology analyses.
- Spilsbury, Sallie (2000). Media Law. Cavendish Publishing. p. p. 439. ISBN 1-85941-530-X. "An individual's signature may be protected under law as an artistic work. If so, the unauthorised reproduction of the signature will infringe copyright. The name itself will not be protected by copyright; it is the appearance of the signature which is protected."
- "Copyright Basics", United States Copyright Office. Retrieved 15 March 2011.
- Spilsbury, Sallie (2000). Media Law. Cavendish Publishing. p. 439. ISBN 1-85941-530-X. "An individual's signature may be protected under law as an artistic work. If so, the unauthorised reproduction of the signature will infringe copyright. The name itself will not be protected by copyright; it is the appearance of the signature which is protected."