The semicolon is the most commonly misused punctuation mark. Bryan Garner (A Dictionary of Modern American Usage) calls the semicolon a “supercomma” because it’s more than a comma.
If you can remember these three uses for a semicolon, you will be a super semicolon user.
- Use a semicolon to separate two independent clauses that are not joined by one of these conjunctions: for, and, nor, but, or, yet, so (think of fanboys as an acronym to remember them all) .
Example: John was the first to cross the finish line; Bob couldn’t find it.
Using one of the conjunctions, the sentence would require a comma:
John was the first to cross the finish line, but Bob couldn’t find it.
- When adverbs like however, therefore, indeed, besides, nevertheless, are used to join two independent clauses, use a semicolon before the adverb.
Example: Bob ran five miles every day; nevertheless he couldn’t keep up with John.
- Use a semicolon to separate items in a list when the items are already separated by commas.
Example: The winners of the marathon hailed from Little Rock, Arkansas; Denver, Colorado; and Kodiak Island, Alaska.
Because a comma is required between the city and state, the city-state entities are separated by semicolons to avoid confusion and comma overload.
Be careful not to confuse a semicolon with a colon. They perform two different functions. The semicolon invites the reader to pause; the colon moves the reader forward. The colon precedes a series of elements that amplify or expand on what comes before the colon. Also make sure to use a colon only after a complete sentence, not a fragment. For example:
Incorrect: My favorite weekend activities include: sleeping in, pigging out, and cheering for the home team.
Correct: I’m looking forward to my weekend activities: sleeping in, pigging out, and cheering for the home team.
On another note, fiction writers often misuse semicolons! The most common misuse is in setting apart a phrase, and what should be used here is an em dash, such as in this example:
Incorrect: He lost his money at the slot machines; every single penny.
Correct: He lost his money at the slot machines—every single penny.
So, try hard not to misuse this tiny bit of punctuation.