Colon vs. Semicolon: Punctuation Smackdown

When a comma is too wimpy and a period is too severe, you need a colon or a semicolon—but which?

Jeeves the Colon

A colon is like a butler: it introduces things. It holds open the door and says, “Mrs. Herringbone to see you, ma’am.” The sight of a colon raises expectations for what is to follow.

• A spelunker must possess the following: a miner’s helmet, a sturdy rope, waterproof boots, and nerves of steel.
• Only one creature in these woods burbles like that: the Jabberwock.
• “Your plan failed, Count Svitavsky, because you forgot one thing: Fifi is allergic to jujubes.”

A spelunker must possess the following: a miner’s helmet, a sturdy rope, waterproof boots, and nerves of steel.

A colon can introduce a list, an example, an explanation, or a conclusion, but remember this: what comes before the colon must be able to stand on its own as a sentence.

• X Their date consisted of: hot dogs, a walk on the beach, and some light larceny.
• ✓ Their date consisted of hot dogs, a walk on the beach, and some light larceny.

• X Over the course of the evening they stole: hip waders, hubcaps, and hairnets.
• ✓ Over the course of the evening they stole hip waders, hubcaps, and hairnets.
• ✓ They stole only items beginning with an h: hip waders, hubcaps, and hairnets.

Semicolons Are for Lovers

When you have two sentences so intimately related they beg not to be apart, join them with a semicolon. But be sure the clauses on both sides of the semicolon are independent—that is, able to stand on their own.

• It was spring; they were in love.
• Jonas chose the toasting fork as his weapon; Tariq selected the spatula.

Jonas chose the toasting fork as his weapon; Tariq selected the spatula.

Don’t make the all-too-common mistake of using a comma where you should use a semicolon. Commas work with coordinating conjunctions like and or but (see Commas and Conjunctions); without a conjunction, you get a painful comma splice.

• X It was spring, they were in love.
• ✓ It was spring and they were in love.

• X Jonas chose the toasting fork as his weapon, Tariq selected the spatula.
• ✓ Jonas chose the toasting fork as his weapon, but Tariq selected the spatula.

Semicolons as Supercommas

Semicolons are sometimes used instead of commas in long, complicated sentences holding multiple clauses, especially when those clauses are themselves already stuffed with commas. In those cases, the semicolons are like extra-emphatic commas.

• Outside the agent’s door stood an astronaut, sweating under his helmet; a ballerina, patting her bun and fluffing her tutu; a nun, her wimple in danger of poking someone’s eye out; and a sasquatch, whose oversized footprints could be seen up and down the hall.
• You could scale the wall with your grappling hook and creep through the mansion on silent feet, unnoticed by the sleeping baron, until you found the hidden room and, using your hard-won skills, opened its lock with your little picks; but you still wouldn’t have a clue how to get inside the safe.

Semicolons with However and That Is

A semicolon is often used before that is (or i.e.), for example (or e.g.), however, therefore, indeed, or similar expressions.

• You’ve eaten the last olive; however, I won’t hold it against you.
• I’m always a considerate neighbour; for example, I never practise the tuba after midnight.
• His new fairy wings were a great success; that is, they worked brilliantly until he hit the ground.

Again, notice that the clauses on both sides of the semicolons could work as separate sentences if they wanted to. Otherwise, the semicolons wouldn’t belong there.

• Mitzi swore she’d become an evil enchantress however long it took.
• Your grandmother is indeed running naked through the park.
• Your grandmother is naked; indeed, she is running through the park.

Mitzi swore she’d become an evil enchantress however long it took.

Match Decision

Sometimes the colon-or-semicolon question can be tough to answer. Does the second clause illuminate the first, or are they just holding hands?

• The mailbox was empty: there was no squid.
• The mailbox was empty; there was no squid.

It’s a question of nuance, and one that you, as a writer, will have to decide for yourself. Or you could just avoid the dilemma by using a period instead.

• The mailbox was empty. There was no squid.

It’s your call.

Support this blog by becoming a patron at patreon.com/grammarlandia.