TexasDesign

Colons are used in Latin and in Romance languages pretty much the same way we use them in English. (Colons caught on in English about the year 1600.) The Latin word “colon” derives from the Greek word that means “limb, member or portion.” Think about that as we go through the various uses of the colon.
By the way, plural for colon in Latin is “cola,” so you could write the name of the soft drink: Coca ::::.
Colons are used to introduce: 1) lists, 2) phrases, 3) subtitles, 4) sentences, 5) generalizations and 6) quotes.
By calling attention to what follows, a colon seems to say, “Sit up and pay attention!” Sometimes the words, “is as follows,” or “the following” can be read where a colon is used.
1. An example of using a colon to introduce a list:
On the day of the exam, don’t forget to bring with you: pencil, ticket and instructions.
2. An example of using a colon to introduce a series of phrases:
The best students always seem to share certain traits: active minds, retentive memories, and curious imaginations.
Notice how the various items in each list are parallel. The three items in the sentence just above are all nouns with single-word adjectival modifiers (”active minds,” for example).
Do not make the list non-parallel. Do not write:
The best students always seem to share certain traits: swimming in the pool, active minds and curiosity.
That statement is both factually and grammatically incorrect.
3. An example of using a colon to introduce a subtitle:
Dr. Strangelove: Or How I Learned to Love the Bomb
That one is self-explanatory. (And an hilarious movie!)
4. An example of using colons to introduce another sentence:
It rained the entire time I was in Moscow: I never got to see Gorky Park.
ExcitingWriting Advisory fans will note that this use of the colon overlaps with a use of the semicolon. You could just as easily and correctly write the above sentence:
It rained the entire time I was in Moscow; I never got to see Gorky Park.
When would you use a colon? When would you use a semicolon?
My view is that you would use a colon if you wanted your reader to come to a complete stop so as to emphasize how the second sentence is the result of the first. You would use a semicolon if you wanted your reader to flow from one sentence to the next and understand a more subtle relationship between the two sentences. I would never use a colon in the “Gorky Park” example above; I would use a semicolon. I don’t like my readers to come to a full stop; I prefer the Texas rolling stop.
Note: If you use a colon with two sentences, you can capitalize the second sentence but you are not obliged to. Be consistent within one piece of writing, however. Both of these examples are correct:
It rained the entire time we were in Moscow: Our vacation was ruined.
It rained the entire time we were in Moscow: our vacation was ruined.
5. An example of using a colon to introduce a generalization:
After going to all that trouble to graduate at the top of her class, what she wanted was finally within her grasp: a treasure trove of job offers she could choose from.
6. An example of using a colon to introduce a quote:
The mayor strenuously objected to the city council’s rebuke: “They will soon hear from the voters of this city, and they may not like what the voters say!”
I much prefer to use a few extra words and a comma rather than a colon when quoting remarks:
The mayor strenuously objected to the city council’s rebuke by saying, “They will soon hear from the voters of this city, and they may not like what the voters say!”
Once again, the colon brings the reader to a full stop. I find it too abrupt for my taste.