Metalinguistic Usage
In mathematics, x is commonly used as the name for an independent variable or unknown value. While it is widely believed that the usage of x to represent an independent or unknown variable can be traced back to the Arabic word šay' شيء = “thing”, there are no sources to support this claim. Modern tradition of using x to represent unknowns was started by Rene Descartes in his La geometrie (1637).
It may also be used to signify the multiplication operation when a more appropriate glyph is unavailable. In mathematics, an "italicized x" is often used to avoid potential confusion with the multiplication symbol.
Other non-mathematical uses include:
- As a result of its use in algebra, X is often used to represent unknowns in other circumstances (e.g. Person X, Place X, etc.; see also Malcolm X).
- X-rays are so called because their discoverer did not know what they were.
- X has been used as a namesake for a generation of humans: Generation X, commonly abbreviated to Gen X. It is the generation born after the baby boom ended, ranging from 1961 to 1981.
- X is also used for referring to 'the end of conversation'.
- X is used by the illiterate in lieu of a signature and indicates a signature line on forms.
- In cartoons, a dead character's eyes are often drawn as Xs.
- X is commonly used as a generic mark (selecting an item on a form, indicating a location on a map, etc.).
- A typographic approximation of the multiplication sign × (especially, lowercase Roman "x"). Note that in any font the glyph of "x" is not exactly the same as one of the multiplication sign.
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Famous quotes containing the word usage:
“...Often the accurate answer to a usage question begins, “It depends.” And what it depends on most often is where you are, who you are, who your listeners or readers are, and what your purpose in speaking or writing is.”
—Kenneth G. Wilson (b. 1923)