How to Use Semicolons

How to Use Semicolons

Semicolon? Half-colon, half-comma, but used like a period? Find out how the semicolon works below.

Semicolons can be confusing, but their use is fairly simple. Sometimes you will have a couple of sentences that are very closely related; they are connected in some way. The sentences are two full complete sentences; therefore a comma does not work. However, there are linked enough that a full period separates them too much.

A semicolon (;) can thus be used to connect two full sentences that are related to each other. The semicolon signifies that the two sentences, while complete, are a linked idea.

Gunpowder was a revolutionizing force in Medieval Europe; it was the end 
of military technology as they knew it.

To use a semicolon to its fullest effect, follow the rules below.

Two Full Ideas

A semicolon should only be used to connect two independent clauses—a phrase with a full subject and predicate, a noun and a verb. The two ideas you are linking should be able to stand on their own. The best way to test this is to replace your semicolon with a period and see if you have two full sentences.

Rome had fallen; the Dark Ages had begun.
Rome had fallen. The Dark Ages had begun.

Two Connected Ideas

The second rule for using a semicolon is that the two ideas you are linking must be related.

Shakespeare was not the only great playwright of his age; Marlowe was also 
a prominent tragedian.
Pablo Picasso was born in 1881; Neil Armstrong was born in 1930.

The first example is a weaker use of a semicolon (a period or other punctuation might be better), but the ideas are closely related. The second example is a poor use of a semicolon, as Picasso and Armstrong are not immediately related figures. Semicolons can be used to set up contrast, but there must still be a connection between the ideas.

Choose Carefully

The final requirement for using a semicolon is to be deliberate with their use. This article has an excess of semicolons in order to demonstrate how to use them. An average paper should have no more than a couple of semicolons. Check with your professor and your assignment guidelines and see if there are any specific directions about semicolons (some instructors may not want them to be used at all).

Having a few semicolons spread throughout your paper can increase its quality. However, using a large amount of them all over your paper will make it seem unprofessional.

Sometimes it is best to not use a semicolon. You do not have to link every pair of sentences with related ideas with a semicolon. In all of the above examples, two sentences could be used instead. Also, depending upon the sentence structure, you might be better served by making a compound sentence or using an em dash.

The Battle of Thermopylae is known for its last stand; Leonidas and 
his Spartans were routed to delay the Persians.

The Battle of Thermopylae is known for its last stand, as Leonidas and 
his Spartans were routed to delay the Persians.

The Battle of Thermopylae is known for its last stand—Leonidas and 
his Spartans were routed to delay the Persians.

Each of these is grammatically correct and reads well. However, each has a slightly different effect. Which structure you decide to use is a matter of personal preference, desired meaning, and following directions.

Semicolon as Super-Comma

Lastly, semicolons have another, distinct use. Semicolons can be used to separate items in a list when the items themselves use commas. This is often used when listing locations (a city followed by the state/country) or a group of multiple items.

The five most populous cities are Tokyo, Japan; Delhi, India; Mexico City, Mexico; 
Osaka, Japan; and Beijing, China. 

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