Placeholder name in the context of List of terms referring to an average person

Alice and Bob are fictional characters commonly used as placeholders in discussions about cryptographic systems and protocols, and in other science and engineering literature where there are several participants in a thought experiment. The Alice and Bob characters were created by Ron Rivest, Adi Shamir, and Leonard Adleman in their 1978 paper "A Method for Obtaining Digital Signatures and Public-key Cryptosystems". Subsequently, they have become common archetypes in many scientific and engineering fields, such as quantum cryptography, game theory and physics. As the use of Alice and Bob became more widespread, additional characters were added, sometimes with particular meanings. These characters do not have to refer to people; they refer to generic agents which might be different computers or even different programs running on a single computer.

John Doe (male) or Jane Doe (female) are multiple-use placeholder names that are used in the British, Canadian, and American legal systems, when the true name of a person is unknown or is being intentionally concealed. In the context of law enforcement in the United States, such names are often used to refer to a corpse whose identity is unknown or cannot be confirmed. These names are also often used to refer to a hypothetical "everyman" in other contexts, like John Q. Public or "Joe Public". There are many variants to the above names, including John (or Richard)/Jane Roe, John/Jane Smith, Joe/Jane Bloggs, and Johnie/Janie Doe or just Baby Doe for children. The gender-neutral A. N. Other is also a placeholder name, mainly used in the United Kingdom.

In linguistics, a placeholder word or a placeholder is a word that is used in place of an exact word. In some cases they are used in speech to replace a forgotten word or a word about which the speaker is unsure. For example the writer may be unsure whether the technical word would be familiar to the readers or the speaker themselves is unsure which word to use. These words, such as "thingummyjig" are not part of standard written language and are not captured well by text corpora. These may replace both names of objects ("thingummabob") and the personal names (placeholder names, e.g., "Mr. Whatshisname"). Placeholder words are often used to convey vagueness. Other means to introduce vagueness are the use of taxonomic nouns with adaptors ("kind of tree"), generic words ("thing", "stuff"), etc. Some authors, e.g., Neil Grave, include generic words ("thing", "stuff") in the category of placeholder words as well. At the same time, Neil Grave notes that the generic words may perform a large number other functions, e.g., to be a vague category marker (as in "shorts and T-shirts, and stuff").

A thorough treatment of vague language, including placeholder words was provided by Joanna Channell. In particular, she demonstrates that dictionaries often provide inadequate definitions and explanations of vague lexical items.

Japanese names (日本人の氏名、日本人の姓名、日本人の名前, Nihonjin no shimei, Nihonjin no seimei, Nihonjin no namae) in modern times consist of a family name (surname) followed by a given name. Japanese names are usually written in kanji, where the pronunciation follows a special set of rules. Because parents when naming children, and foreigners when adopting a Japanese name, are able to choose which pronunciations they want for certain kanji, the same written form of a name may have multiple readings. In exceptional cases, this makes it impossible to determine the intended pronunciation of a name with certainty. Even so, most pronunciations chosen for names are common, making them easier to read. While any jōyō kanji (with some exceptions for readability) and jinmeiyō kanji may be used as part of a name, names may be rejected if they are believed to fall outside what would be considered an acceptable name by measures of common sense.

Japanese names may be written in hiragana or katakana, the Japanese language syllabaries for words of Japanese or foreign origin, respectively. As such, names written in hiragana or katakana are phonetic rendering and lack meanings that are expressed by names written in the logographic kanji.

In linguistics, a filler, filled pause, hesitation marker or planner is a sound or word that participants in a conversation use to signal that they are pausing to think but are not finished speaking. These are not to be confused with placeholder names, such as thingamajig. Fillers fall into the category of formulaic language, and different languages have different characteristic filler sounds. The term filler also has a separate use in the syntactic description of wh-movement constructions (see below).

Japanese names (日本人の氏名、日本人の姓名、日本人の名前, Nihonjin no shimei, Nihonjin no seimei, Nihonjin no namae) in modern times consist of a family name (surname) followed by a given name. Japanese names are usually written in kanji, where the pronunciation follows a special set of rules. Because parents when naming children, and foreigners when adopting a Japanese name, are able to choose which pronunciations they want for certain kanji, the same written form of a name may have multiple readings. In exceptional cases, this makes it impossible to determine the intended pronunciation of a name with certainty. Even so, most pronunciations chosen for names are common, making them easier to read. While any jōyō kanji (with some exceptions for readability) and jinmeiyō kanji may be used as part of a name, names may be rejected if they are believed to fall outside what would be considered an acceptable name by measures of common sense.

Japanese names may be written in hiragana or katakana, the Japanese language syllabaries for words of Japanese or foreign origin, respectively. As such, names written in hiragana or katakana are a phonetic rendering and lack meanings that are expressed by names written in the logographic kanji.

A tanmono (反物（たんもの）) is a bolt of traditional Japanese narrow-loomed cloth. It is used to make traditional Japanese clothes, textile room dividers, sails, and other traditional cloth items.

Tanmono (物, mono is a placeholder name) are woven in units of tan, a traditional unit of measurement for cloth roughly analogous to the bolt, about 35–40 centimetres (14–16 in) by about 13 yards (12 m). One kimono takes one tan (ittan) of cloth to make. Tanmono are woven in the narrow widths most ergonomic for a single weaver (at a handloom without a flying shuttle).

Unidentified decedent, or unidentified person (also abbreviated as UID or UP), is a corpse of a person whose identity cannot be established by police and medical examiners. In many cases, it is several years before the identities of some UIDs are found, while in some cases, they are never identified. A UID may remain unidentified due to lack of evidence as well as absence of personal identification such as a driver's license. Where the remains have deteriorated or been mutilated to the point that the body is not easily recognized, a UID's face may be reconstructed to show what they had looked like before death. UIDs are often referred to by the placeholder names "John Doe" or "Jane Doe". In a database maintained by the Ontario Provincial Police, 371 unidentified decedents were found between 1964 and 2015.

This is a list of English-language placeholder names for people. A variety of such placeholder names are used in the English language, some with respect to the average unnamed person, and some with specialized meanings such as reference to people in particular professions. Some morphologists "will distinguish between placeholders such as thingummy and placeholder names like John Doe".