Colons in References, Times, Ratios, and Titles

by Craig Shrives

Colons in References, Ratios, Times, and Titles

Colons are used as separators in references, times, ratios, and titles

Colons in References

In a biblical reference, a colon separates chapter from verse. For example:
  • Genesis 1:1 starts "In the beginning God created the heavens and the earth."
  • (Note there is no space before or after the colon.)
A colon is also used as a separator in a reading references. In a reading reference, the colon usually separates the volume from the page numbers.
  • This topic is covered in Encyclopaedia Britannica 3:21-23.
  • (This means volume 3 pages 21-23.)
Here is another example of colons used in a reference:
  • Learn Chapter XIV:Section 4:Paragraph 6 by tomorrow.
  • (There is no established format or ruling. Remember that colons in references are just separators for you to use.)

Colons in Ratios

A ratio between two or more quantities is a way of measuring their sizes compared to each other. A ratio is shown with a colon as a separator. For example:
  • It's myth that the ratio of women to men in Nottingham is 6:1.
  • 5:3 is close to the Golden Ratio, which is represented by the Greek letter phi (Φ)
The first number of a ratio is called the "antecedent." The second number is called the "consequent."


In times, colons are used in timings greater than a minute. For example:
  • The happiest hour of the day is between 19:00 and 20:00.
  • (Here, the colon separates hours and minutes.)
  • The marathon world record is 2:02:57.
  • (Here, the colons separate hours, minutes, and seconds.)
  • The 800m world record is 1:40.91.
  • (In this example, the colon separates minutes and seconds. Note that tenths of a second are not separated by a colon but a point.)
In times of the day, using a period or nothing is also a common convention. For example:
  • The alarm clock is set for 07:30.
  • (0730 and 07.30 are also common.)

Colons in Titles

In titles, a colon is often used to separate the main title from the subtitle. For example:
  • "Pirates of the Caribbean: Dead Man's Chest"
  • "How To Get Your Own Way: Who's Manipulating You?"
  • "Grammar Rules: Writing with Military Precision"
Note that a semicolon, a comma, and "or" are also commonly used to separate a title from a subtitle. Colons often make better separators than the alternatives.
colons as separators in references, times, ratios, and titles

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