Asterisk

This article refers to the typographical symbol. For other uses, see Asterisk (disambiguation).

An asterisk (*), is a typographical symbol or glyph. It is so called because it resembles a conventional image of a star (Latin astrum). Computer scientists and mathematicians often pronounce it as star (as, for example, in the A* search algorithm or C* algebra).

The asterisk derives from the need of the printers of family trees in feudal times for a symbol to indicate date of birth. The original shape was six-armed, each arm like a teardrop shooting from the center. For this reason, in some computer circles it is called a splat, perhaps due to the "squashed-bug" appearance of the asterisk on many early line printers.

The Unicode standard states that the asterisk is distinct from the Arabic five pointed star (U+066D), the asterisk operator (U+2217), and the heavy asterisk (U+2731).^[1]

Many cultures have their own unique version of the asterisk. In Japan a character with a similar use looks like an X with dots surrounding it. This mark looks like the Chinese character for rice: 米. The Arabic asterisk is six-pointed. In some fonts the asterisk is five-pointed and the Arabic star is eight-pointed.

The symbols are compared below (the display depends on your browser's font).

Asterisk	Heavy Asterisk	Small Asterisk	Full Width Asterisk	Open Centre Asterisk
*	✱	﹡	＊	✲

Math/Low Asterisk	Arabic star	Japanese "rice" star	Teardrop-Spoked Asterisk	Sixteen Pointed Asterisk
∗	٭	※	✻	✺

Usage

Written text

The asterisk is used to call out a footnote, especially when there is only one on the page. Less commonly, multiple asterisks are used to denote different footnotes on a page. (i.e., *, **, ***)
Three spaced asterisks centered on a page may represent a jump to a different scene or thought. See Horizontal rule.
One or more asterisks may be used to replace portions of a profanity to reduce offence such as the word being beeped or censored for. Example: S**t
It is also common to use asterisks as bullets for list items.
Asterisks can be used to *emphasize*.
also referred to as "Upper K Star". This definition/term is/was used by many instructors of Electric Keyboarding.
Asterisks can also be used as scoring system, eg. in movie reviews. See Star (classification).

Linguistics

Historical linguistics

In historical linguistics, an asterisk next to a word indicates that the word is not directly attested, but has been reconstructed on the basis of other linguistic material (see also historical linguistics, comparative method).

Generativist tradition in linguistics

In generativism, especially syntax, an asterisk next to a word or phrase indicates that the word or phrase is ungrammatical.

Computing

Computer science

In computer science, the asterisk is used in regular expressions to denote zero or more repetitions of a pattern; this use is known as the Kleene star or Kleene closure after Stephen Kleene.

In the Unified Modeling Language, the asterisk is used to denote zero to many classes.

Computer interfaces

In some computer interfaces, such as the Unix shell and Microsoft's Command prompt, the asterisk is the wildcard character and stands for any string of characters. This is also known as a wildcard symbol. A common use of the wildcard is in searching for files on a computer. For instance, if a user wished to find a document called Document 1, search terms such as Doc* and D*ment* would return this file.

In some graphical interfaces, particularly Microsoft applications, an asterisk is prepended to the current working document name shown in a window's title bar to indicate that unsaved changes exist.

In Commodore (and related) filesystems, an asterisk appearing next to a filename in a directory listing denotes an improperly closed file, commonly called a "splat file."

Programming languages

Many programming languages and calculators use the asterisk as a symbol for multiplication. It also has a number of special meanings in specific languages, for instance:

In some programming languages such as the C programming language, the asterisk is used to dereference or to declare a pointer variable.
In the Common Lisp programming language, the names of global variables are conventionally set off with asterisks, *LIKE-THIS*.
In the Fortran programming language, and in some dialects of the Pascal programming language, a double asterisk is used to signify exponentiation: 5**3 is 5*5*5 or 125.
In the Perl programming language, the asterisk is used to refer to the typeglob of all variables with a given name.
In the programming languages Ruby and Python, * has two specific uses. Firstly, the unary * operator applied to a list object inside a function call will expand that list into the arguments of the function call. Secondly, a parameter preceded by * in the parameter list for a function will result in any extra parameters being aggregated into a tuple (Python) or array (Ruby).

Mathematics

The asterisk has many uses in mathematics. The following list is not exhaustive.

The complex conjugate of a complex number (though a more common notation is ${\bar {z}}$ ^{[citation needed]}).
The free product of two groups.
Infix notation for an arbitrary binary operator.
Convolution, e.g. f ∗ g is a convolution of f with g.
The multiplicative group of a ring, especially when the ring is a field. E.g. $\mathbb {C} ^{*}=\mathbb {C} -\{0\}$
An arbitrary point in some set, for example in computing Riemann sums or when contracting a simply connected group to the singleton set { ∗ }.
The dual space of a vector space V is denoted V*.
The combination of an indexed collection of objects into one example, e.g. the combination of all the cohomology groups H^k(X) into the cohomology ring H*(X).
The pushforward (differential) of a smooth map f between two smooth manifolds is denoted f_*.
The Hodge dual operator on vector spaces $*:A^{k}\rightarrow A^{n-k}$ .

The asterisk is also often used, in all branches of mathematics, to designate a correspondence between two mathematical entities represented by a single letter — one with the asterisk and one without.

Mathematical typography

In fine mathematical typography, the Unicode character U+2217 (∗) "math asterisk" is available (HTML entity &lowast;). This character also appeared in the position of the regular asterisk in the PostScript symbol character set in the Symbol font included with Windows and Macintosh operating systems and with many printers. It should be used in fine typography for a large asterisk that lines up with the other mathematical operators.

A group of three asterisks arranged in a triangular formation is called an asterism.

Human genetics

In human genetics, * is used to denote that someone is a member of a haplogroup and not any of its subclades (see * (haplogroup)).

Telephony

On a Touch-Tone telephone keypad, the asterisk (called star, or less commonly, palm or sextile^[2]) is one of the two special keys, and is found to the left of the zero (the other is the number sign (pound sign or hash or, less commonly, octothorp^[2])).

E-mail, Usenet, IM

In lieu of typographical formatting denoting emphasis (e.g., commonly, italics), a word or phrase may be bracketed by asterisks *like this*, especially in e-mail or other text-based communications where multiple typefaces are not available — i.e. in plain text.
In informal written communications, particularly those via e-mail, instant messaging, or BBS, asterisks are often used to bracket a predicate denoting the performance of an action, to indicate that the person typing is performing that action. Example: *writes a wikipedia article*. Rather than a well-formed predicate in the third person singular, sometimes just the simplest form of the verb is used (e.g. *jump* or *glomp*), especially in text RPGs where unformatted text denotes speech. Compare with the usage of the colon.
In chatrooms and instant messaging, an asterisk is often used to correct a typo. Usage varies on whether the asterisk comes before or after the correction. For example:

Alice: What do yuo think

Alice: *you

Bob: Wht,

Bob: Wha?*

Note that because Bob wishes to correct himself again, he may decide to use two asterisks to show that his first correction was in reality, not correct.

Bob: What?**

As in written text, asterisks may be used as bullets for list items.

Cricket

In cricket, it signifies a total number of runs scored by a batsman without losing his wicket, e.g. 107* means '107 not out'. When written before a player's name on a scorecard, it indicates the captain.

It is also used on television when giving a career statistic during a match. For example, 47* in a number of matches column means that the current game is the player's 47th.

Economics

In economics, the use of an asterisk after a letter indicating a variable such as price, output, or employment indicates that the variable is at its optimal level (that which is achieved in a perfect market situation). For instance, p* is the price level p when output y is at its corresponding optimal level of y*.

Education

In the GCSE examination and PSLE, A* ("A-star") is a special top grade that is distinguished from grade A.

Games

Certain categories of character types in role-playing games are called splats, and the game supplements describing them are called splatbooks. This usage originated with the shorthand "*book" for this type of supplement to various World of Darkness games, such as Clanbook: Ventrue (for Vampire: The Masquerade) or Tribebook: Black Furies (for Werewolf: The Apocalypse), and this usage has spread to other games with similar character-type supplements. For example, Dungeons & Dragons Third Edition has had several lines of splatbooks: the "X & Y" series including Sword & Fist and Tome & Blood prior to the "3.5" revision, the "Complete X" series including Complete Warrior and Complete Divine, and the "Races of X" series including Races of Stone and Races of the Wild.
In many MUDs and MOOs, as well as "male", "female", and other more esoteric genders, there is a gender called "splat", which uses an asterisk to replace the letters that differ in standard English gender pronouns. For example, h* is used rather than him or her. Also, asterisks are used to signify doing an action, for example, "*action*"

Baseball

In recent years, the asterisk has come into use on scorecards to denote a "great defensive play."^[3]
In colloquial usage, an asterisk is used to indicate that a record is somehow tainted by circumstances, which are putatively explained in a footnote supposedly referenced by the asterisk.^[4] This usage arose after the 1961 baseball season in which Roger Maris of the New York Yankees broke Babe Ruth's 34-year-old single-season home run record. Because Ruth had amassed 60 home runs in a season with only 154 games, compared to Maris's 61 over 162 games, baseball commissioner Ford Frick announced that Maris' accomplishment would be recorded in the record books with an explanation (often referred to as "an asterisk" in the retelling). In fact, Major League Baseball has no official record book, but the stigma remained with Maris for many years, and the concept of a real or figurative asterisk denoting less-than-official records has become widely used in sports and other competitive endeavors. A 2001 TV movie about Maris's record-breaking season was called 61* (pronounced sixty-one asterisk) in reference to the controversy. Fans critical of Barry Bonds also taunted him with asterisks as he approached Hank Aaron's career home run record.
Asterisks, in relation to professional sports records, were ranked No. 12 overall in the book "Glow Pucks & 10-Cent Beer: The 101 Worst Ideas in Sports History" by author Greg Wyshynski (Taylor Trade 2006).

Horse Racing

In programs distributed at race tracks, an asterisk next to a jockey's name indicates that he or she is an apprentice, and in many cases is allowed to ride at a slightly lesser weight than the other jockeys. Such a jockey is sometimes called a “bug boy” for obvious reasons.

Pop Culture

David Crowder Band often includes an asterisk in their logo as such: David Crowder*Band
The Red Hot Chili Peppers use an 8-pronged asterisk as their symbol.
The name of the Boy band NSYNC is often stylized as "*NSYNC" or "N*SYNC".
The popular Japanese Hip Hop/Rock group Orange Range has a song titled "*~Asterisk", which is also the first opening theme song for the popular anime Bleach.
In the King of The Hill episode "Bills Are Made To Be Broken", Hank Hill pleads for an asterisk next to a football record in the record books: "Mr. Chairman, I would like to respectfully submit that you put an asterisk next to Ricky Suggs's name in the record book. And that asterisk should read: This record was attained through the use of fraud and bad sportsmanship."
The fictional comic-book character, Asterix the Gaul, is a pun on Asterisk as he is the "star" of the show.^{[citation needed]}
In an episode of Everybody Loves Raymond, Ray Barone (portrayed by Ray Romano) recognizes that he pronounces the word "Asterisk" "Astericks". This was never corrected in future episodes but Ray Barone never spoke the word again.
In Pat Cadigan's novel Synners, a character sees a sign that says "U B THE *" and reads it as "You Be the Ass To Risk".
In a song by Lil Wayne called "Back On My Grizzy" from, his mixtape "Da Drought 3", he says in a line "I'm a crazy ass star like a fucking asterisk"

Encodings

	Unicode	Decimal	UTF-8	HTML
Asterisk	U+002A	*	2a
Small Asterisk	U+FE61	﹡	ef, b9, a1
Full Width Asterisk	U+FF0A	＊	ef, bc, 8a
Asterisk Operator (Math Asterisk)	U+2217	∗	e2, 88, 97	&lowast;
Heavy Asterisk	U+2731	✱	e2, 9c, b1
Open Centre Asterisk	U+2732	✲	e2, 9c, b2
Eight Spoked Asterisk	U+2733	✳	e2, 9c, b3
Sixteen Pointed Asterisk	U+273A	✺	e2, 9c, ba
Teardrop-Spoked Asterisk	U+273B	✻	e2, 9c, bb
Open Centre Teardrop-Spoked Asterisk	U+273C	✼	e2, 9c, bc
Heavy Teardrop-Spoked Asterisk	U+273D	✽	e2, 9c, bd
Four Teardrop-Spoked Asterisk	U+2722	✢	e2, 9c, a2
Four Balloon-Spoked Asterisk	U+2723	✣	e2, 9c, a3
Heavy Four Balloon-Spoked Asterisk	U+2724	✤	e2, 9c, a4
Four Club-Spoked Asterisk	U+2725	✥	e2, 9c, a5
Heavy Teardrop-Spoked Pinwheel Asterisk	U+2743	❃	e2, 9d, 83
Balloon-Spoked Asterisk	U+2749	❉	e2, 9d, 89
Eight Teardrop-Spoked Propeller Asterisk	U+274A	❊	e2, 9d, 8a
Heavy Eight Teardrop-Spoked Propeller Asterisk	U+274B	❋	e2, 9d, 8b
Arabic star	U+066D	٭	d9, ad
Japanese "Rice" Star	U+203B	※	e2, 80, bb
Tag Asterisk	U+E002A	󠀪	f3, a0, 80, aa

References

^ Detailed descriptions of the characters [The ISO Latin 1 character repertoire]
^ ^a ^b US 3920926
^ Baseball Almanac - Scoring Baseball: Advanced Symbols
^ See e.g. Allen Barra (May 27, 2007). "An Asterisk Is Very Real, Even When It's Not". New York Times.

Letter Database, source for encodings