Colon (punctuation)

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The colon (":") is a punctuation mark, visually consisting of two equally sized dots centered on the same vertical (up/down) line.

Punctuation[change | change source]

Use in prose[change | change source]

A colon is a more significant pause than a semi-colon. It is often used to contrast two parts of a sentence:

  1. It's official: McClaren makes the worst start by an England manager.[1]
  2. When the door was forced, a scene of chaos was revealed: chairs overturned, drawers pulled oun and emptied, broken crockery on the floor...
  3. If you must go, take the following: climbing rope, ice axe, compass, a large-scale map, emergency water and food, and good boots.
  4. Man proposes: God disposes.
  5. The Lord seeth not as man seeth: for man looketh on the outward appearance, but the Lord looketh on the heart.

These two examples were lists within a sentence. A colon may also be used for the following:

Use in other kinds of text[change | change source]

  • introduction of a definition, such as:
A: the first letter in the Latin alphabet
Hypernym of a word: a word having a wider meaningm than the given one; e.g. vehicle is a hypernym of car
  • separation of the chapter and the verse number(s) indication in many references to religious scriptures, and also epic poems; it was also used for chapter numbers in roman numerals, as in:
John 3:14–16 (or John iii:14–16) (cf. chapters and verses of the Bible)
The Qur'an, Sura 5:18
  • separation when reporting time of day hour/minute/second (cf. ISO 8601), such as:
The concert finished at 23:45.
This file was last modified today at 11:15:05.
  • separation of a title and the corresponding subtitle, as in:
Star Wars Episode IV: A New Hope
  • separation of clauses in a periodic sentence
  • Colons can also be used to start a list, such as, "He provided all of the ingredients: sugar, flour, eggs and butter."
  • KERRY-ANNE: They're freckles, Philip. How many more times?

History[change | change source]

The colon's first appearance in English text is marked by the Shorter Oxford English Dictionary as 1589.

Diacritical usage[change | change source]

The IPA length mark

A special double-triangle colon symbol is used in IPA to indicate that the preceding sound is long. Its form is that of two triangles, each a bit larger than a point of a standard colon, pointing toward each other. It is available in Unicode as modifier letter triangular colon, Unicode U+02D0 (ː). A regular colon is often used as a fallback when this character is not available, or in the practical orthography of some languages (particularly in Mexico) which have a phonemic long/short distinction in vowels.

Mathematics[change | change source]

The colon is also used in mathematics, cartography, model building and other fields to denote a ratio or a scale, as in 3:1 (pronounced "three to one"). Unicode provides a distinct ratio character, Unicode U+2236 () for mathematical usage.

In many non-Anglophone countries, the colon is used as a division sign: "a divided by b" is written as a : b.

The combination with an equal sign, :=\,, is used for definitions.

Computing[change | change source]

In computing, the colon character is represented by ASCII code 58, and is located at Unicode code-point U+003A. The full-width (double-byte) equivalent, , is located at Unicode code point U+FF1A.

The colon is quite often used as a special control character in many operating systems commands, URLs, computer programming languages, and in the path representation of several file systems. It is often used as a single post-fix delimiter, signifying a token keyword had immediately preceded it or the transition from one mode of character string interpretation to another related mode. Some applications, such as the widely used MediaWiki, utilize the colon as both a pre-fix and post-fix delimiter.

For a double-colon, "::" the meaning has included the use of ellipsis, as spanning over omitted text; however, there have been other meanings as well.

Internet usage[change | change source]

On the Internet (online chats, email, message boards, etc.) a colon, or multiple colons, is sometimes used to denote an action or emote. In this use, it has the inverse function of quotation marks; denoting actions where unmarked text is assumed to be dialog. For example:

Tom: Pluto is so small, it should not be considered a planet. It is tiny!
Dick: Oh really? ::Drops Pluto on Tom's head:: Still think it's small now?

Colons may also be used for sounds (as with ":Click:"). Compare to the use of outer asterisks (*word*).

It also has the widespread usage of representing two vertically aligned eyes in a emoticon, such as :-), :( :P, :D, :3, etc.

References[change | change source]