A solidus, oblique or slash, /, is a punctuation mark. It is also called a diagonal, separatrix, shilling mark, stroke, virgule, slant, or forwardslash.
This symbol goes back to the days of ancient Rome. In the early modern period, it was the predecessor of the comma in the German language.
The most common use is to replace the hyphen to make clear a strong joint between words or phrases, such as "the Ernest Hemingway/William Faulkner generation". Yet very often it is used to represent the concept or, especially in instruction books.
The symbol also appears in the phrase and/or, a prose representation of the logical concept of inclusive or. The State Legislature of Georgia, however, has banned its use in this word as cumbersome.
For a specialized use of the slash in the titles of fan fiction stories, see slash fiction.
A virgule is used to separate the numerator and denominator in a vulgar fraction, or as a division operator in general.
- 3/8 – three eighths
- x = a / b – x equals a divided by b
Note that the special character Fraction slash U+2044, character ⁄ (the solidus or shilling mark proper), can be used instead of a virgule, and is preferred whenever possible. It is also found in many legacy Apple Macintosh character sets. Systems capable of fine typography should display the result as a true fraction with smaller numbers. Unicode also distinguishes the Division Slash U+2215 (∕) which may be more oblique than the normal solidus character.
The slash is used to separate directory or names in Unix file paths and in URLs.
It is sometimes called a "forward slash" to contrast with the backslash \ which is the path delimiter on MS-DOS and Microsoft Windows systems. Windows uses the backslash rather than the slash because in the early days of DOS — before directories were supported — the slash was chosen as the command-line option indicator:
- dir /w /ogn c:\windows\
Note, however, that the "forward slash" is also accepted as a path delimiter by most versions of DOS and Windows, in most contexts where there is no ambiguity with command-line options.
Non-technical people often sloppily and incorrectly refer to a slash as a "backslash", for instance when reading URLs out loud, which can be infuriating to those who understand that the two characters are different.
In computer programming, the solidus corresponds to Unicode and ASCII character 47, or 0x002F. It is used in the following settings:
- In most programming languages, / is used as a division operator,
- In C (1999 standard) and C-like languages, // (two slashes) is used to begin a single-line comment.
- In HTML and XML, a slash is used to indicate a closing tag. For example, in HTML, </b> ends a section of bold text started with <b>.
Slash is the first part of SlashDot.org, an iconic web site (http://slashdot.org), that draws on the symbolism in the *nix command of going back to the root... directory/anything/of the issue/etc.
Certain shorthand date formats use / as a delimiter, for example "9/16/2003" (in United States usage) or "16/9/2003" (in many other countries) means September 16, 2003.
In Britain there was a specialized use in prose: 7/8 May referred to the night which starts the evening of 7 May and ends the morning of 8 May, totalling about 12 hours depending on the season. This was used to list night-bombing air-raids which would carry past midnight. Some police units in the US use this for night disturbances or chases. Contrariwise, the form with a hyphen, 7-8 May, would refer to the two-day period, at most 48 hours. This would commonly be used for meetings.
Problems with the use of the slash in dates has been compounded by the International Standard ISO 8601, accepted by both the Germans as DIN 5008 and by the Europeans as European Standard EN 28601. These norms prescribe writing dates using hyphens, but time periods are written using the slash: 1939-09-01/1945-05-08, for example, would be the duration Second World War in the European theatre, while 09-03/12-22 might be used for a fall term of a Western school, from September third to December twenty-second.
Before decimalisation in the UK, / was used to separate pounds, shillings, and pence values. Notice how the dash is used to represent zero.
|2/6 ||two shillings and six pence |
|10/- ||ten shillings |
|£1/19/11 ||one pound, nineteen shillings, and eleven pence |
In the UK, the usual term for the mark is an oblique, although slash is gaining currency with increasing use of computers and also through the media, such BBC Radio.
Sometimes this is called stroke, although that may be confused with the hyphen.