The Semicolon Does One Job, and It Does It Well

The semicolon has a reputation for difficulty it does not deserve. There are two uses. They are unrelated, which is the only genuinely confusing thing about it.

Use one: joining two complete sentences

When two sentences are closely connected, a semicolon joins them without a conjunction.

• The meeting ran late; nobody minded.
• She had prepared for weeks; it showed.

The test: both halves must stand alone as sentences. If you can replace the semicolon with a full stop and both sides still work, you have used it correctly.

So what does it add over a full stop? Closeness. A full stop says new thought. A semicolon says same thought, second half. The reader carries the first clause into the second rather than setting it down.

Use two: separating items that already contain commas

When list items have internal commas, commas between them stop working:

• Unreadable: We visited Paris, France, Rome, Italy, and Madrid, Spain.
• Clear: We visited Paris, France; Rome, Italy; and Madrid, Spain.

This is sometimes called the serial semicolon, and it is the one use nobody argues about. It also dissolves most serial comma disputes, since a list punctuated with semicolons is unambiguous either way.

The comma splice it prevents

The most common error a semicolon fixes:

• Wrong: The plan was sound, it failed anyway.
• Right: The plan was sound; it failed anyway.
• Also right: The plan was sound, but it failed anyway.
• Also right: The plan was sound. It failed anyway.

A comma cannot join two independent clauses on its own. It needs a conjunction, or it needs to become a semicolon or a full stop.

However, therefore, and the rest

Words like however, therefore, nevertheless, moreover and consequently look like conjunctions and are not. They cannot join clauses with a comma:

• Wrong: It rained, however we went anyway.
• Right: It rained; however, we went anyway.
• Right: It rained. However, we went anyway.

This is the single most common semicolon situation in professional writing, and getting it right is worth more than any stylistic use.

Two things it cannot do

It cannot introduce. That is the colon’s job. She had one goal; to finish is wrong. She had one goal: to finish is right.

It cannot attach a fragment. The report was late; because of the printer is wrong, because the second half is not a sentence. Use a comma, or nothing at all.

On the advice to avoid them

Kurt Vonnegut said semicolons represent absolutely nothing and only show you have been to college. It is a good line and it is advice about a particular kind of writing — spare, plain, deliberately unliterary.

For most prose the semicolon does something a full stop cannot: it holds two ideas in the same breath. Used two or three times in an essay it is invisible and useful. Used in every paragraph it becomes a tic, which is true of every punctuation mark and not a reason to abandon this one.

Checked against Merriam-Webster, the Chicago Manual of Style and the AP Stylebook. Spotted an error? Tell us — see our editorial policy.