Metasyntactic Variable

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- "John Doe"

A Metasyntactic Variable -- also called a "Placeholder Name" -- is a word or phrase used in the place of another word or phrase in any of several contexts. By mathematical analogy, a metasyntactic variable is a word that is a variable for other words, just as in algebra letters are used as variables for numbers.

In computing and technology contexts, these words are commonly found in source code and are intended to be modified or substituted before real-world usage. The words foo and bar are good examples as they are used in over 330 Internet Engineering Task Force Requests for Comments, the documents which define foundational internet technologies like HTTP (websites), TCP/IP, and email protocols. Metasyntactic variables are used to name entities such as variables, functions, and commands whose exact identity is unimportant and serve only to demonstrate a concept, which is useful for teaching programming. A short examination of Metasyntactic Variables as used in computing can be found at the Coding Horror blog.

Outside of computing contexts, these are words that functional grammatically as nouns and that can refer to objects, places or people whose names do not exist, are temporarily forgotten, irrelevant, or unknown in the context in which they are being discussed. This can include such terms as "watchamacallit", "thingamabob", "dojiggy" and "wossname" (the latter being primarily a UK usage), or a term as simple as "thing". Most of these words can be documented to at least the 19th century.

Some fields have their own specific placeholder terminology. For example, "widget" in economics, engineering and electronics, or "Blackacre" and "John Doe" or "Jane Doe" in law.

Compare with Bland-Name Product, where the variable is based on a Real Life brand name and the reader or viewer is expected to notice the reference; The Trope Without a Title, in which a description (sometimes so vague as to be meaningless) is used instead of a name; and Buffy-Speak, where the speaker is making up what sound like metasyntactic variables on the fly because he can't remember (or never knew) the actual terms.

Advertising

 * "Brand X" is used in television advertisements as a generic brand representing any other brand than the one being advertised.

Fan Works

 * Can be found in play twice in the title of the Harry Potter/Doctor Who Crossover fic Potter Who and the Wossname's Thingummy.

Film

 * Fictional brands such as Morley are often used in film and television as placeholders to avoid unintended Product Placement.
 * "Mammoth Studios" was a common name for a nonexistent film studio in the 1930s and 1940s (and later in TV series scripts in the 1960s). The name made it through script re-writes on a few occasions.

Literature

 * Edgar Allan Poe wrote a short story entitled "The Literary Life of Thingum Bob, Esq.", showing that particular form to be in familiar use in the United States in the 1840s.

Live-Action TV

 * The "X" in the title of The X-Files is a Metasyntactic Variable referring to the unknown and possibly paranormal aspects of the cases within those files.
 * "Oceanic Airlines" -- most famously seen in Lost but used as early as 1965 in Flipper -- is used as a "placeholder" fictional airline in films, TV programs, and comic books, typically when a plane is involved in a disaster or another event with which actual airlines would prefer not to be associated. The Other Wiki has a page listing uses of this name.

Theatre
"... apologetic statesmen of a compromising kind, Such as: What d'ye call him: Thing'em-bob, and likewise: Never-mind, and 'St: 'st: 'st: and What's-his-name, and also You-know-who: The task of filling up the blanks I'd rather leave to you."
 * In Gilbert and Sullivan's The Mikado, W. S. Gilbert makes the Lord High Executioner sing of a "little list" which includes:

Web Original

 * The Jargon File has an extensive entry on the subject that documents not just American and British usage but terms used by programmers from continental Europe and New Zealand.
 * The Russian FIDO community Kaschenko came up with "Shooshpanchik", which was a meme spontaneously evolved from a taunt to one user (who in the end apparently was proud of it). Shooshpanchik is a subset of living creatures, but does not have a more specific meaning. Typically it was used to mutate jokes (e.g. "Hedgehog is an ancient and chthonic animal" could be transformed into "Shooshpanchik is an ancient and metasyntactic animal") or as a substitute "classification" for something made up (one short scene from Star Wars prequels was summarized as "Two shooshpanchiks graze near the spaceship. Male one and female one. They symbolize.").
 * This spawned derivatives, such as "shushpanzer" (шушпанцер), which means more or less "armored vehicle that looks weird or improvised and obviously doesn't fit well into classifications", "shushpancycle" ("шушпанцикл", the same for motorcycles and other small wheeled vehicles) and "shushpangewehr" ("шушпангевер", the same for firearms, especially long arms).
 * All The Tropes (and TV Tropes before us) has a history of using the word "trope" as a Metasyntactic Variable in trope names, such as The Trope Kid, Disney Owns This Trope and The Von Trope Family. TVT began discouraging this practice long before the fork leading to ATT took place, and many such names were later replaced, but we still have a dozen or so lurking about, and have even added a couple of our own, such as Tropacabana.
 * We also have the trope Foo Fu, where "Foo" is the classic programmer's Metasyntactic Variable, standing for any mundane item or skill which could be used in some awesome, often combat-related, way.

Real Life

 * Metasyntactic variables used commonly across all programming languages include foobar, foo, bar, baz, qux, quux, quuz, corge, grault, garply, waldo, fred, plugh, xyzzy, and thud.
 * Wibble, wobble, wubble, and flob are also used in the UK.
 * Japanese programmers commonly use hoge (ほげ) and piyo (ぴよ), with other common words and variants being fuga (ふが), hogera (ほげら), and hogehoge (ほげほげ).
 * In France, the word toto is widely used by programmers, with variants tata, titi, and tutu as related placeholders.
 * The Whatchamacallit bar, a chocolate/peanut butter/caramel candy bar introduced by Hershey in 1978, uses a Metasyntactic Variable as its name to emphasize what at the time of its release was a candy bar allegedly radically different from any produced before.
 * Hershey also briefly produced a chocolate-peanut butter bar called the Thingamajig, which was available from 2009 to 2012.
 * "X-ray" was originally a placeholder name for an unexplained phenomenon, with "X" representing, as in algebra, the unknown.
 * It is common to use the name "ACME" in example SQL Databases and as placeholder company-name for the purpose of teaching. The term 'ACME Database' is commonly used to mean a training or example-only set of database data used solely for training or testing. ACME is also commonly used in documentation which shows SQL usage examples, a common practice with in many educational texts as well as technical documentation from companies such as Microsoft and Oracle.
 * "Advent corporation" is a term used by lawyers to describe an as yet unnamed corporation, while legal incorporation documents are being prepared.
 * The very real Advent Corporation (active 1967-1981) got its name when its founder liked the sound of the placeholder.
 * Discussions about cryptography - especially cryptographic procedures - usually use the same two names as metasyntactic variables for the sender and recipient of a message: Alice and Bob.