Semicolons

Semicolons have three main uses.

1. Use the semicolon to join two independent clauses with related ideas. The semicolon signals that a qualifying or subtly related idea connects the second clause to the first.

“Inherently, food is ethically neutral; notions of good and bad, healthy and unhealthy are projected onto it by culture” (Maxfield 446).

2. Use the semicolon and a conjunctive adverb or transitional phrase to connect independent clauses. The adverb or phrase indicates the relationship between the ideas expressed. The adverb or phrase is preceded by a semicolon and followed by a comma.

“Divergent thinking is not a synonym for creativity; however, divergent thinking is a thought process that lends itself to creative thought” (Roy 76).

When used mid-sentence, the adverb is preceded and followed by a comma:

“Not all of the projects examined, however, focused on only one medium” (Vogt and Mitchell). 

3. Use the semicolon to separate items in a series or list when the individual items contain internal punctuation.

“New theories beget new drugs to treat diabetes, high blood pressure, and cholesterol; new treatments and procedures to ameliorate chronic diseases; and new diets organized around each new theory’s elevation of one class of nutrient and demotion of another” (Pollan 422).

Colons

Colons have a wider variety of uses than semicolons. Colons may be used following an independent clause to introduce a list, an explanation, an appositive, or a quotation. Colons also may be used as punctuation between two independent clauses.

1. Use the colon to introduce a list or an explanation. The language preceding the colon must form an independent clause.

“Venezuela’s collapse has many causes: excessive borrowing, political corruption, an official exchange rate that defies economic realities” (Casselman).

“If you are like me, a fan of American middleness, Wichita is your kind of place: an El Dorado of hamburger stands, alliterative city slogans, pork tenderloin sandwiches, souped-up trucks, old-school diners, bowling alleys, and steakhouses with Spandex-clad waitresses” (Frank 56).

2. Use the colon to introduce an appositive, a word, or words that rename a noun or pronoun. Again, the construction preceding the colon must be an independent clause. 

“Fully 73% of Americans distinguish between astronomy and what is commonly considered a pseudoscience: astrology” (Funk and Goo). 

3. Use the colon to introduce a quotation. The language preceding must form an independent clause.

Pew Researchers Kennedy and Funk found a perception of neutrality: “Most Americans say they think of scientists as neither politically liberal nor conservative.”

4. Use the colon to link two independent clauses, a first that contains a general assertion to a second that is more specific or provides evidence to support it. (When you begin the second independent clause, capitalization is generally considered optional. Check the style manual in your field.)

Kristol reported that “there was virtually no change in the voters’ ideological self-identification: in 2008, 22 percent called themselves liberal, up only marginally from 21 percent in 2004; 34 percent were conservative, unchanged from the last election; and 44 percent called themselves moderate, compared with 45 percent in 2004.”

5. Colons are used for a variety of punctuation purposes. Several common uses follow.
   • Title and subtitle
     • Canada: Our Friendly Neighbor to the North
   • Salutations in formal letters
     • Dear Mrs. Collins:
   • Hours, minutes, and seconds
     • Our flight for Washington departed at 10:49 a.m.
     • The Kenyan track star ran the mile in 3:47:08.
   • Cities and publishers in bibliographic entries
     • Boston: Bedford, 2008
   • Biblical chapters and verses
     • Chase mulled Ecclesiastes 6:12, which reads, "For who knoweth what is good for man in this life, all the days of his vain life which he spendeth as a shadow? For who can tell a man what shall be after him under the sun?”

Colon Miscues

The colon is most often misused when a writer places one in a sentence between a verb and its object or complement. Problems also occur when writers place a colon following such as, include, or including. Always check to make sure the language preceding the colon is an independent clause. If not, omit.