For the next tip in our Fearless Punctuation Series, we reveal the hidden power of the colon to emphasize and elaborate. We encourage you to use the colon daringly, yet sparingly, to spice up your writing.
H.W. Fowler said that the colon “delivers the goods that have been invoiced in the preceding words,” which is as apt a description as any! More specifically, colons introduce the part of a sentence that exemplifies, restates, elaborates, undermines, explains or balances the preceding statement. Most importantly, that ‘preceding statement’ must always be an independent clause capable of standing alone. Never use a colon after a sentence fragment.
A writer may use a colon after an independent clause to direct the reader’s attention to a list, an appositive, or a quotation.
The Bren School’s MESM core curriculum includes the following fall courses: Ecology of Managed Ecosystems, Earth Systems Science, Introduction to Environmental Policy Analysis, and Business and the Environment.
When examined in this way, climate change is a violation of nature: an appalling mistake.
Consider the words of P.J. O’Rourke: “The college idealists who fill the ranks of the environmental movement seem willing to do absolutely anything to save the biosphere, except take science courses and learn something about it.”
A colon may also be used between independent clauses if the second clause summarizes or explains the first.
The environmental assessment was correct: most of the habitat had been destroyed.
Note: When an independent clause follows a colon, it may begin with a lowercase or a capital letter.
~Other More Perfunctory Uses~
The colon is also used after a salutation in a formal greeting letter, to indicate hours and minutes, to show proportions, between a title and subtitle, and in certain conventions in bibliographic entries (volume: page number, city: publisher, etc.).
Dear Ms. Helfer:
The standard ratio of nitrogen to phosphorus in marine systems is 16:1.
Eats, Shoots & Leaves: The Zero Tolerance Approach to Punctuation
Boston: Bedford, 1999.
As mentioned above, a colon MUST be preceded by an independent clause.
Avoid using a colon between a verb and its object or complement.
Some important nutrients in aquatic systems are: phosphorus and nitrogen. (Incorrect)
Some important nutrients in aquatic systems are phosphorus and nitrogen. (Correct)
Avoid using a colon between a preposition and its object.
Particulate matter (PM10) pollution consists of: very small liquid and solid particles floating in the air. (Incorrect)
Particulate matter (PM10) pollution consists of very small liquid and solid particles floating in the air. (Correct)
Avoid using a colon after "such as," "including," or "for example."
The Burton Mesa Ecological Reserve is home to native plant species such as: Arctostaphylos purissima and Ceanothus cuneatus var. fascicularis. (Incorrect)
The Burton Mesa Ecological Reserve is home to native plant species such as Arctostaphylos purissima and Ceanothus cuneatus var. fascicularis. (Correct)
Hacker, D. 1999. A Writer’s Reference. Fourth Edition. Boston: Bedford/St. Martin’s.
Jeantheau, M. 2010. Funny Environmental Quotes. Grinning Planet. Web. http://www.grinningplanet.com/environmental-quotes/funny-environmental-quotes.htm
Truss, L. 2003. Eats, Shoots & Leaves: The Zero Tolerance Approach to Punctuation. Gotham Books: New York City.