A numeronym is a number-based word.
Anne H. Soukhanov, editor of the Microsoft Encarta College Dictionary, gives the original meaning of the term as "a telephone number that spells a word or a name" on a telephone dial/numpad.
A number may also denote how many times the character before or after it is repeated. This is typically used to represent a name or phrase in which several consecutive words start with the same letter, as in W3 (World Wide Web) or W3C (World Wide Web Consortium).
Types
Homophone
Most commonly, a numeronym is a word where a number is used to form an abbreviation (albeit not an acronym or an initialism). Pronouncing the letters and numbers may sound similar to the full word, as in "K9" (pronounced "kay-nine") for "canine, relating to dogs".
Examples
sk8r: Skater
B4: Before
l8r: Later; L8R, also sometimes abbreviated as L8ER, is commonly used in chat rooms and other text based communications as a way of saying goodbye. G2G: "Good to go", "got to go", or "get together" P2P: "pay to play" or "peer-to-peer" F2P: "free to play" T2UL/T2YL: "talk to you later" B2B: "business to business" B2C: "business to consumer"
Numerical contractions
Alternatively, letters between the first and last letters of a word may be replaced by a number representing the number of letters omitted, such as in "i18n" for "internationalization", where "18" stands in for the word's middle eighteen letters ("nternationalizatio"). Sometimes the last letter is also counted and omitted. These word shortenings are sometimes called alphanumeric acronyms, alphanumeric abbreviations, or numerical contractions. According to Tex Texin, the first numeronym of this kind was "S12n", the electronic mail account name given to Digital Equipment Corporation (DEC) employee Jan Scherpenhuizen by a system administrator because his surname was too long to be an account name. By 1985, colleagues who found Jan's name unpronounceable often referred to him verbally as "S12n" (ess-twelve-en). The use of such numeronyms became part of DEC corporate culture.
Examples
Where words have multiple meanings, abbreviations such as these are almost always used to refer to their computing sense; for example, G11n for "globalization" refers to software preparedness for global distribution, and not the social trend of globalization. g11n – globalisation / globalization i14y – interoperability a11y – accessibility m12n – modularisation / modularization p13n – personalization s5n – shorten h7k – hyperlink l10n – localisation i18n – internationalization a16z – Andreessen Horowitz K8s – Kubernetes o11y – Observability (software) c12s – Communications c14n – Canonicalization
Numeric numeronyms
Some numeronyms are composed entirely of numbers, such as "212" for "New Yorker", "4-1-1" for "information", "9-1-1" for "help", "101" for "basic introduction to a subject", and "420" for "Cannabis". Words of this type have existed for decades, including those in 10-code, which has been in use since before World War II. Chapter or title numbers of some jurisdictions' statutes have become numeronyms, for example 5150 and 187 from California's penal code. Largely because the production of many American movies and television programs are based in California, usage of these terms has spread beyond its original location and user population.
Examples
64 – Tiananmen Square protests of 1989
143 – I love you
187 – slang for "murder", based on section 187 of the California Penal Code. 520 – I love you (one of many numeronyms used in Chinese Internet Slang)
SI-style numeronyms
As long numbers (e.g. 1.000 or 1.000.000) are often abbreviated by using a unit (e.g. 1k), they also naturally found their way into numeronyms. One advantage of these numeronyms is that you can use them in places where you can also use alphanumeric characters, so you can't use a grouping separator to easily read the number.
Examples
Y2K problem – Year 2000 problem
Y2K38 problem – Year 2038 problem
Other examples
In some cases, the use of appropriate case makes it easier to distinguish between letters such as uppercase "I" (eye) and lowercase "l" (el). 8′46″ – The length of time associated with the murder of George Floyd (May 25, 2020 in Minneapolis). E15 – The Eyjafjallajökull volcano in Iceland