These placeholders typically function grammatically as nouns and can be used for people (e.g. John Doe, Jane Doe), objects (e.g. widget), locations ("Main Street"), or places (e.g. Anytown, USA). They share a property with pronouns, because their referents must be supplied by context; but, unlike a pronoun, they may be used with no referent—the important part of the communication is not the thing nominally referred to by the placeholder, but the context in which the placeholder occurs.
Stuart Berg Flexner and Harold Wentworth's Dictionary of American Slang (1960) use the term kadigan for placeholder words. They define "kadigan" as a synonym for thingamajig. The term may have originated with Willard R. Espy, though others, such as David Annis, also used it (or cadigans) in their writing. Its etymology is obscure—Flexner and Wentworth related it to the generic word gin for engine (as in the cotton gin). It may also relate to the Irish surname Cadigan. Hypernyms (words for generic categories; e.g. "flower" for tulips and roses) may also be used in this function of a placeholder, but they are not considered to be kadigans.
Placeholder words exist in a highly informal register of the English language. In formal speech and writing, words like accessory, paraphernalia, artifact, instrument, or utensil are preferred; these words serve substantially the same function, but differ in connotation. Borrowed from French is je ne sais quoi ("I know not what").
Most of these words can be documented in at least the 19th century. 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. In Gilbert and Sullivan's The Mikado, W. S. Gilbert makes the Lord High Executioner sing of a "little list" which includes:
... 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.
Some fields have their own specific placeholder terminology. For example, "widget" in economics, engineering and electronics or "Blackacre" and John or Jane Doe in law. "X-ray" was originally a placeholder name for an unexplained phenomenon.
Dark matter: the postulated matter of unknown form which likely makes up the majority of the matter in the UniverseDark energy: the postulated energy of unknown form which is responsible for the accelerating expansion of the UniverseLGM-1 and LGM-2 (the latter also called "WTF") for unexplained observationsPlanet X (disambiguation): various hypotheses about the existence of an undetected planetCompanies and organizations
"Ace" and "Acme" were popular in company names as positioning words in alphabetical directories. They were generic, laudatory of whatever products they were used to promote and appeared at the beginning of most alpha-sorted lists. The Acme Corporation of cartoon fame is one placeholder example. ("Acme" – a regular English word from the Greek "akme" meaning summit, highest point, extremity or peak and thus sometimes used for "best")."Mom and Pop" (in the United States) are occasional placeholders for the individual owners of a generic, very small family businessMain Street or High Street for the business district of a small town or village, often contrasted as a commercial business entity against Wall Street as the financial market of New York City."Advent corporation" is a term used by lawyers to describe an as yet unnamed corporation, while legal incorporation documents are being prepared. In case of Advent Corporation, founder Henry Kloss decided to adopt this placeholder name as the formal legal name of his new company."NewCo" or "Newco" is used in a similar way in British English for an as yet unnamed company.Fictional brands such as Morley (cigarette) are often used in television and cinema as placeholders to avoid unintended product placement."XYZ Widget Company" has long been used in business and economic textbooks as a sample company. Also used as engraving text example on items such as plaques, trophy plates, etc. Occasionally appears on customizable promotional materials including stationery templates, business cards, advertising signage, cups, backpacks, and other "swag" samples.Placeholder names are commonly used in computing:
Foo, Bar, Baz, and Qux (and combinations thereof) are commonly used as placeholders for file, function and variable names. Foo and bar probably relate to FUBAR.Hacker slang includes a number of placeholders, such as frob which may stand for any small piece of equipment. To frob, likewise, means to do something to something. In practice it means to adjust (a device) in an aimless way.Alice and Bob, alternatives for 'Person A'/'Person B' when describing processes in telecommunications; in cryptography Eve (the eavesdropper) is also added.J. Random X (e.g. J. Random Hacker, J. Random User) is a term used in computer jargon for a randomly selected member of a set, such as the set of all users. Sometimes used as J. Random Loser for any not-very-computer-literate user.Johnny Appleseed, commonly used as a placeholder name by Apple.Contoso is a fictional company name commonly used as an example in Microsoft documentation.Domain names
Certain domain names in the format example .tld (such as example.com, example.net, and example.org) are officially reserved as placeholders for the purpose of presentation. Various example reserved IP addresses exist in IPv4 and IPv6, such as 2001:db8: in IP6 documentation.
Placeholders such as "Main Street", "Your County", and "Anytown" are often used in sample mailing addresses. Ruritania is commonly used as a placeholder country.
Something-stan, where something is often a curse word, is commonly used as a placeholder for a Middle Eastern or South Asian country or for a politically disliked portion of one's own country.
Timbuktu, which happens to be a real city, is often used to mean a place that is far away, in the middle of nowhere, and/or exotic.
Podunk is used in American English for a hypothetical small town regarded as typically dull or insignificant, a place that you have likely never heard of, though still in the United States.
In Australian English, Woop-Woop is the placeholder name for an out of the way town.
John Doe and the variations Jane Doe (for females) and John Roe or Richard Roe (for a second party): used in legal action and cases when the true identity of a person is unknown or must be withheld for legal reasons. "Jane Roe" was used for the then-unidentified plaintiff (Norma Leah McCorvey) in one of the most famous legal cases in United States history, Roe v. Wade.Mopery: used in informal legal discussions as a placeholder for some infraction, when the exact nature of the infraction is not important.Blackacre and its neighbors Whiteacre, Greenacre, Brownacre, Greyacre, Pinkacre, etc. are used as placeholders for parcels of real property, usually on Law School examinations and the several State Bar Exams. They are sometimes located in Acre County in the fictional State of Franklin.SQUIFFO is used as a placeholder name for a trade mark by trade mark lawyers and agents.The man on the Clapham omnibus: a hypothetical reasonable person, used by the courts in English law where it is necessary to decide whether a party has acted as a reasonable person would.Bug: any insect, arthropod, or germ. However, true bugs belong to the order HemipteraCritter (dial., creature): any animal, usually a small mammalVarmint (dial., vermin): any despised animal, usually a small mammalSt. Elsewhere is often used as a placeholder name for any regional hospital, or other care facility from which an admitted patient was referred. The medical slang is honored in the name of the 1980s television show of the same name.GOMER (get out of my emergency room) is a name in medical slang for any patient who continually uses emergency room services for non-emergency conditions; its use is informal and pejorative.Often used in example names and addresses to indicate to the serviceman where to put his own details.
Tommy Atkins, the generic name for a soldier of the British Army. Also, colloquially, Bill Oddie, rhyming slang on the nickname 'squaddie'.In the American Army and Air Force, Private (or Airman) Tentpeg and Snuffy are commonly used in examples (to explain various procedures) or cautionary tales. In the Marine Corps, Lance Corporal Schmuckatelli serves the same purpose.In the U.S. Coast Guard, a generic Coast Guardsman is referred to as Joe Coastie (or Jane).In the Coast Guard, Navy, and Marines, a hypothetical member who has his act together is A.J. Squared-Away.In the Canadian Armed Forces, the generic name for a soldier is Private/Corporal/rank BlogginsUmpteen is any annoyingly large number, as in the phrase "for the umpteenth time". While perhaps being larger than nineteen, umpteen is still generally recognized to be several orders of magnitude smaller than fake numbers ending in -illion, as in zillion or jillion.Placeholder telephone numbers are often allocated from ranges such as 555 (telephone number) (where +1-areacode-555-1212 is reserved in North America for directory assistance applications) to avoid generating misdialled calls to working numbers. In the United Kingdom, Ofcom has set aside a range of numbers in larger geographic area codes, as well as fictional area code 01632 (0632 having been the code for Newcastle upon Tyne until replaced by 091 in the 1980s), for dramatic use.Common placeholders for postcodes in Canada include A1A 1A1 (a real postal code for Lower Battery Road, St. John's, Newfoundland) and K1A 0B2 (Canada Post Place in Ottawa). In the United States, the ZIP Code 90210 (from TV series Beverly Hills 90210) is frequently used. Numeric codes with repeated or sequential digits like 12345 (Schenectady, New York), or 99999-9999 may also appear.black box, an indeterminate device where only its input and output matter and the way it works does notcontraption, a large man-made machineCumsiecom: a rendition of the Italian phrase come si chiama, literally "what do you call it", which may refer to a thing or a stuffDingusdingbat, an old-fashioned term for a random or unidentifiable object, [2] as referenced in James Thurber's "The Owl in the Attic".[3]doodad, used for indeterminate small man-made objects about the size of a cellular phone (may be electronic or not)doohickeygewgaw, an indeterminate piece of jewelrygizmogubbinsHoojamawichKajigger Used on the TV show Futurama.NESOI, NESI, or NES, acronyms short for Not Elsewhere Specified (or Indicated). Used in categorizing items, for example in:Food and Agriculture Organization Corporate Statistical DatabaseHarmonized Tariff Schedule for the United StatesjawnoojamaflipThe word “Smurf” is the original Dutch translation of the French "Schtroumpf", which, according to Peyo, is a word invented during a meal, when he could not remember the word salt.thingamajig, thingumabob or thingamajiggery.thingyveeblefetzer, from a Yiddish word meaning "contraption" (In Mad magazine, a fictional company called "North American Veeblefetzer" was often used as a means to satirize business practices.)whatchamacallitwhatsitwidget, referring to some theoretical object. It was originally most commonly used in describing the output of a hypothetical business; in computer technology, it refers to any arbitrary item that may be made to appear on the screen.yoke (in Ireland)John DoeReligion and philosophy
Mumbo jumbo: rituals performed by a priest of a religion that one does not believe in that are performed in a language that one is unfamiliar with. Can also be used about legal writing that a person does not understand or perceives as needlessly long-winded ("Legal mumbo jumbo")Hocus pocus: This is currently used by magicians, usually the magic words spoken when bringing about some sort of change.Abracadabra: A specific magical phrase, but also used generically.The suffix -ism is often used (as a whole word) for a generic religious, ideological or philosophical concept, since so many such concepts end in "-ism".Little green men or LGM: unspecified extraterrestrialsBug-eyed monster or BEM: a hostile alien, often depicted as having large, bug-like eyesThere are many idioms in many languages which use a noun phrase to designate a long time or never: "a month of Sundays", "the twelfth of never", "the Greek calends".
Spoken and written language
Cloud cuckoo land: a proposal that the speaker regards as foolish or impractical. A rough translation of Nephelococcygia which appears in the ancient Greek play The Birds by Aristophanes.double Dutch: Incomprehensible languageFolderol: foolish or silly talkGibberish, jibber jabber: content that makes no sense to anyoneGobbledygook: text whose wording is so complex as to be meaningless, often usedas a way for the writer to appear intelligent, orperhaps most often when the writer has not thought the subject matter through enough or taken the trouble to express it in an understandable way, ordeliberately to prevent the audience from understanding it.Lorem ipsum: Simulated text used to fill in for written content in a page layout designWord salad: an incomprehensible series of words and phrases. While usually used when resulting from mental illness, it is sometimes used to other incomprehensible speech