List with colon
The primary purpose of the colon is to signal that a list will follow.
If what comes before the list is a complete sentence, then use the colon before the list.
If what introduces the list is not a complete sentence without the list, do not use the colon.
Examples using a colon:
- My brother’s birthday list had only five items: a new bicycle, a new wagon, a new cell phone, a remote-controlled airplane, and a pony.
- Wikipedia divides United States history into several sections: the colonial period, the 18th century, the American Revolution, the early years of the Republic, the 19th century, the 20th century, and the 21st century.
- Savannah had four choices of occupations: nurse, librarian, secretary, or teacher.
- Benjamin considered the following names for his puppy: Snitch, Snappy, Stub, and Spook.
With a list of movies or books with titles and subtitles (set off with colons), it would be preferable to introduce the list with a dash.
- The theatre advertised an all-day viewing of these movies—Superman IV: The Quest for Peace, Highlander 2: The Quickening, Speed 2: Cruise Control, and Teenage Mutant Ninja Turtles II: The Secret of the Ooze.
Do NOT use a colon if the list itself completes the sentence, if the list itself is the object of the verb or the preposition.
- For his birthday, my brother wanted a new bicycle, a new wagon, a new cell phone, a remote-controlled airplane, and a pony.
- (“My brother wanted” is not a finished thought.)
- Wikipedia divides United States history into the colonial period, 18thcentury, American Revolution, early years of the Republic, 19thcentury, 20thcentury, and 21stcentury.
- (“Wikipedia divides United States history into” is not a complete thought.)
- Savannah was considering nursing, teaching, being a librarian, or being a secretary.
- (“Savannah was considering” is not a complete thought.)
- Benjamin’s preferred names for his new puppy included Snitch, Snappy, Stub, and Spook.
- (“Benjamin’s preferred names for his new puppy included” is not a complete thought.)
Sometimes the list only contains one item, something that describes or explains the first part of the sentence (which is still a complete thought without the item).
The item itself may be a complete sentence, but it must relate and add to the first.
- Benjamin only wanted one thing for his birthday: a pony.
- Benjamin’s mother accepted his final choice to name his pony: Stub.
- Savannah settled on the one occupation that seemed possible: nursing.
- I had only one thought in mind: I could escape by digging a tunnel.