Colons: when to use them
Phil Druker, Department of English,
University of Idaho
Mainly we use colons to introduce lists. Some formal copy editors insist that colons only follow complete sentences, but in normal practice this isn’t necessary.
- To
introduce lists.
 | To complete the objectives, we plan to take these steps: |
1. Perform secondary research
2. Develop a basic design
3.
Refine the design using these calculations:
a.
Stress
b. Sheer
c.
Fatigue
4. Build the scale model
5. Test the scale model
6. Write the results.
** Remember to use parallelism with lists. (Note how all the elements in the list above start with verbs—action words.)
- To
separate clauses and give emphasis.
·
His reason for accepting the lowest-paying job offer was simple:
he always wanted to live in the Northwest.
- To
introduce an explanation
·
I want you to understand one point:
colons emphasize the idea that follows them.
- To
introduce quotations
· He always believed in the precept: “To thine own self be true.”
This works especially to introduce long quotations.
Some examples on using Colons
:
Use
colons to draw attention to a list or very closely related information.
Usually, you use colons after complete sentences.
Example 1:
Ok
but wordy:
She is an ideal colleague. She is honest, dependable,
and competent.
Better:
She
is an ideal colleague: honest, dependable, and competent.
Example 2:
Wrong:
We performed tasks, such as: electrophoresis, MRI
imaging, and cellular tomography.
We performed these tasks: electrophoresis, MRI imaging,
and cellular tomography.
Example 3:
Inappropriate use of a colon plus wordy:
Three principal methods of research have been used in order to better identify population structure. These are: radio telemetry, genetic studies, and analysis of the manatee photo identification scar catalogue.
Better:
Three principal methods of research have been used in order to better identify population structure: radio telemetry, genetic studies, and analysis of the manatee photo identification scar catalogue.