A typographical error (often shortened to typo) is a mistake made in, originally, the manual type-setting (typography

Typography

Typography is the art and technique of arranging type in order to make language visible. The arrangement of type involves the selection of typefaces, point size, line length, leading , adjusting the spaces between groups of letters and adjusting the space between pairs of letters...

) of printed material, or more recently, the typing

Typing

Typing is the process of inputting text into a device, such as a typewriter, cell phone, computer, or a calculator, by pressing keys on a keyboard. It can be distinguished from other means of input, such as the use of pointing devices like the computer mouse, and text input via speech...

 process. The term includes errors due to mechanical failure or slips of the hand or finger, but usually excludes errors of ignorance, such as spelling error

Orthography

The orthography of a language specifies a standardized way of using a specific writing system to write the language. Where more than one writing system is used for a language, for example Kurdish, Uyghur, Serbian or Inuktitut, there can be more than one orthography...

s. Before the arrival of printing, the "copyist's mistake" or "scribal error" was the equivalent for manuscript

Manuscript

A manuscript or handwrite is written information that has been manually created by someone or some people, such as a hand-written letter, as opposed to being printed or reproduced some other way...

s. Most typos involve simple duplication, omission, transposition, or substitution of a small number of characters.

The term fat finger, often in combination with "fat-finger syndrome", is used as slang to refer to the invocation of a unwanted secondary action due to (a) one's finger being bigger than the envisioned touch zone, or (b) accidental inaccuracy in the fine motor movements of one's extremities. In general terms, for example, pressing a different button than expected on a touchscreen, or hitting two adjacent keys on a keyboard

Keyboard (computing)

In computing, a keyboard is a typewriter-style keyboard, which uses an arrangement of buttons or keys, to act as mechanical levers or electronic switches...

 in a single keystroke during data entry (for example, buckled instead of bucked due to the adjacency of the L key to the K key on many keyboards). Especially in light of the trend in e.g. mobile phones always getting smaller, the etymology for the fat finger term may root in the fact that users with naturally-grown big fingers, as well as obese users, are one of the first groups to run into problems of this miniaturization.

"Intentional" typos

Certain typos, or kinds of typos, have achieved widespread notoriety and are occasionally used deliberately for humorous purposes. For instance, the British newspaper The Guardian

The Guardian

The Guardian, formerly known as The Manchester Guardian , is a British national daily newspaper in the Berliner format...

is sometimes referred to as The Grauniad due to its reputation for frequent typesetting errors in the era before computer typesetting. This usage began as a running joke in the satirical magazine Private Eye

Private Eye

Private Eye is a fortnightly British satirical and current affairs magazine, edited by Ian Hislop.Since its first publication in 1961, Private Eye has been a prominent critic and lampooner of public figures and entities that it deemed guilty of any of the sins of incompetence, inefficiency,...

. The magazine continues to refer to The Guardian by this name to this day.

Typos are common on the internet in chatrooms, Usenet

Usenet

Usenet is a worldwide distributed Internet discussion system. It developed from the general purpose UUCP architecture of the same name.Duke University graduate students Tom Truscott and Jim Ellis conceived the idea in 1979 and it was established in 1980...

 and the World Wide Web

World Wide Web

The World Wide Web is a system of interlinked hypertext documents accessed via the Internet...

 and some, such as "teh

Teh

Teh is an Internet slang neologism most frequently used as an English article, based on a common typographical error of "the". Teh has subsequently developed grammatical usages distinct from the...

", "pwned", and "pron" have become in-joke

In-joke

An in-joke, also known as an inside joke or in joke, is a joke whose humour is clear only to people who are in a particular social group, occupation, or other community of common understanding...

s among Internet groups and subcultures.

Typosquatting

Typosquatting is a form of cybersquatting

Cybersquatting

Cybersquatting , according to the United States federal law known as the Anticybersquatting Consumer Protection Act, is registering, trafficking in, or using a domain name with bad faith intent to profit from the goodwill of a trademark belonging to someone else...

 which relies on typographical errors made by Internet users. Typically, the cybersquatter will register a plausible typo of a well-known website address in hopes of receiving traffic when Internet users mistype that address into a web browser

Web browser

A web browser is a software application for retrieving, presenting, and traversing information resources on the World Wide Web. An information resource is identified by a Uniform Resource Identifier and may be a web page, image, video, or other piece of content...

. Deliberately introducing typos into a web page, or into its metadata

Metadata

The term metadata is an ambiguous term which is used for two fundamentally different concepts . Although the expression "data about data" is often used, it does not apply to both in the same way. Structural metadata, the design and specification of data structures, cannot be about data, because at...

, can also draw unwitting visitors when they enter these typos in Internet search engines.

Typos in online auctions

Since the emergence and popularization of online auction sites such as eBay

EBay

eBay Inc. is an American internet consumer-to-consumer corporation that manages eBay.com, an online auction and shopping website in which people and businesses buy and sell a broad variety of goods and services worldwide...

, misspelled auction searches have quickly become a gold mine for deal hunters. The concept on which these searches are based is that if an individual posts an auction and misspells its description and/or title, regular searches will not find this auction. However, a search which includes misspelled alterations of the original search term in such a way as to create misspellings, transpositions, omissions, double strikes, and wrong key errors would find most misspelled auctions. The resulting effect is that there are far fewer bids than there would be under normal circumstances allowing for the searcher to obtain the item for less. A series of third party web sites have sprung up allowing people to find these items.

Marking typos

When using a typewriter

Typewriter

A typewriter is a mechanical or electromechanical device with keys that, when pressed, cause characters to be printed on a medium, usually paper. Typically one character is printed per keypress, and the machine prints the characters by making ink impressions of type elements similar to the pieces...

 without correction tape

Correction tape

Correction tape is an alternative to correction fluid used to correct mistakes during typing, or, in some forms, handwriting. One side of the tape, which is placed against the error, is coated in a white, opaque masking material...

, typos are commonly overstruck

Overstrike

In typography, overstrike is a method of printing characters that are missing from the printer's character set. It was widely used around the early 1990s...

 with another character such as a slash

Slash (punctuation)

The slash is a sign used as a punctuation mark and for various other purposes. It is now often called a forward slash , and many other alternative names.-History:...

. This saves the typist the trouble of retyping the entire page to eliminate the error, but as evidence of the typo remains, it is not aesthetically pleasing.

In instant messaging

Instant messaging

Instant Messaging is a form of real-time direct text-based chatting communication in push mode between two or more people using personal computers or other devices, along with shared clients. The user's text is conveyed over a network, such as the Internet...

, users often send messages in haste and only afterwards notice the typo. It is common practice to correct the typo by sending a subsequent message where an asterisk

Asterisk

An asterisk is a typographical symbol or glyph. It is so called because it resembles a conventional image of a star. Computer scientists and mathematicians often pronounce it as star...

 precedes or follows the correct word.

In such forms of teleprinter

Teleprinter

A teleprinter is a electromechanical typewriter that can be used to communicate typed messages from point to point and point to multipoint over a variety of communication channels that range from a simple electrical connection, such as a pair of wires, to the use of radio and microwave as the...

 that have no backspace or delete key (particularly those that use Baudot code

Baudot code

The Baudot code, invented by Émile Baudot, is a character set predating EBCDIC and ASCII. It was the predecessor to the International Telegraph Alphabet No 2 , the teleprinter code in use until the advent of ASCII. Each character in the alphabet is represented by a series of bits, sent over a...

), an error that is caught immediately will be followed by 'X' repeated a few times, as a sort of representation of the mistake being exed out, with the correct spelling following, for example:

This js XXXX is an example.

In formal prose it is sometimes necessary to quote accurately text containing typos. In such cases, the author will usually write "[sic

Sic

Sic—generally inside square brackets, [sic], and occasionally parentheses, —when added just after a quote or reprinted text, indicates the passage appears exactly as in the original source...

]" to indicate that an error was in the original quoted source rather than in the transcription.

Thumbo

A thumbo is a typographical error made during thumb typing, especially on the keypads of cellphones and smartphone

Smartphone

A smartphone is a high-end mobile phone built on a mobile computing platform, with more advanced computing ability and connectivity than a contemporary feature phone. The first smartphones were devices that mainly combined the functions of a personal digital assistant and a mobile phone or camera...

s. With minimal spacing in between alphabets on thumbing keypads, one tends to type wrong letters, thus the error. The word is a portmanteau of "thumb" and "typo".