What is a forward slash called and how is it used?

Question: What is a forward slash called and how is it used?

Answer: Most commonly referred to as slash or forward slash, its proper name is solidus or virgule. Slash is the most common term but it is sometimes also called a diagonal. The solidus is a punctuation mark used as a separator, a word substitute, for mathematic expressions, and in Web addresses (URL or Uniform Resource Locator). See the following examples:

• As a separator for dates:
  My birthdate is 11/04/58.
  He briefly played for the Cowboys during the 1998/99 season.

• As a separator for quoted lines of poetry:
  She kept repeating, "I never saw a purple cow/ I never hope to see one/ But I can tell you anyhow/ I'd rather see than be one."
  Note that the solidus is always followed by a space in this usage and should normally be restricted to no more than 3 or 4 lines of poetry.

• As a word substitute:
  150 mi./sec (miles per second)
  and/or (and or or)

• As a word substitute (or) to indicate choice:
  Student/Employee, Y/N, he/she
  Often seen as a sign of sloppy writing, refer to your prescribed style guide for help.

• Informally as an abbreviation:
  w/ (with)
  Avoid this usage in serious writing.

• As a mathematical symbol:
  • Solidus may be used to separate the numerator and denominator of an inline or diagonal fraction as in 1/4 (one-fourth).

  • A proper division slash is a more slanted diagonal slash used to represent division as in 400 ⁄ 10 (400 divided by 10).

    Some sources refer to the division slash as the fraction slash and suggest it be used for inline fractions as well.

    When the division or fraction slash is unavailable in a font, using an italic solidus may be an acceptable alternative.

• In a Web address:
  http://desktoppub.about.com/cs/
  expertcharacters/f/solidus.htm
  (the URL for this page)

• In HTML and other programming languages:
  <b>This text is bold</b> and <i>This is italic</i> in an HTML document would result in: This text is bold and This is italic in a Web browser - the slash telling the browser where to end the bold and italic text.

Some style guides omit or explicitly restrict some of the uses described above. Check the style guide in use for your publication before using the forward slash. Frequently the solidus is used when a comma, hyphen, and, or, or are the best choices.