Semicolons are often seen as a strange and mysterious punctuation mark; they’re part period and part comma. So why use them? They’re useful to break up the stylistic approach to sentence structure, allowing writers to combine two related thoughts, often removing a word or two in the process. They’re also important for clarity purposes when too many commas start being used—the semicolon can create more obvious visual separation between complex list items or items that use commas between them (like cities and states).

Terms You Need to Know to Use Semicolons

COMPLETE SENTENCES (INDEPENDENT CLAUSES)
A complete sentence is a sentence that contains a subject and a verb and expresses an entire thought. A complete sentence can be an independent clause or an independent clause with other clauses added.

COMPLEX LIST ITEMS
Complex list items are items that usually contain multiple elements. Complex items in a list usually contain a list themselves or other information that makes a simple list impossible.

3 Ways to Use Semicolons

Join Two Related Complete Sentences
Separate Complex List Items
Separate List Items that Already Include Commas

1. Join Two Related Complete Sentences

DESCRIPTION
A complete sentence is a sentence that contains a subject and a verb and expresses an entire thought. A complete sentence can be an independent clause or an independent clause with other clauses added. One use of a semicolon is to join two complete sentences that are related to one another.

APPLICATION
To join two related complete sentences, put a semicolon at the end of one sentence and before the beginning of the second. The semicolon should take the place of where a period would be separating the sentences.

EXAMPLE

Alexandra attended her first design class; it changed her career outlook completely.
(In this sentence, it was Alexandra’s design class that changed her career outlook. These two independent clauses (complete sentences) relate to each other so, stylistically, the sentences can be joined with a semicolon.)

NOTE: In the example above, it would be mechanically correct to also use a period between the two sentences. The use of a semicolon is a stylistic choice that reads a bit more smoothly and makes a clear connection for the reader between the two sentences. Because there is an independent clause on BOTH sides of the semicolon, you must use either a period or a semicolon. Using a comma would be incorrect (joining two complete sentence with a comma is known as a comma splice, which you want to avoid).

2. Separate Complex List Items

DESCRIPTION
If you want to write a list, but you find that each item in the list is fairly descriptive or complex (and may need to include commas within a description of a single list item), you’ll want to use semicolons to separate each list item for clarity.

APPLICATION
To use a semicolon to separate items in a complex list, put a semicolon after each complex item in a list.

EXAMPLE

If I were to name my three favorite meals, they would include first, a hamburger, fries, and Coke; second, pizza with tomatoes, olives, and green peppers; and third, meatloaf with mashed potatoes and gravy.
(In this sentence, there are three list items, but each list item includes descriptions that require commas. The semicolon separates each list item for clarity.)

3. Separate List Items that Already Include Commas

DESCRIPTION
Semicolons can separate list items that already require commas to separate information, like cities and states. This use is related to separating complex list items (see #2 above), but not all complex lists contain commas.

APPLICATION
To use a semicolon to separate list items with commas, simply put a semicolon after each list item, as you would put a comma after an item in a simple list.

EXAMPLE

Over the summer, Alisa traveled to San Francisco, California; Las Vegas, Nevada; and Colorado Springs, Colorado.
(In this sentence, the cities and states require commas to separate them, so when listing them out semicolons are needed to help prevent confusion.)