A semicolon acts as a break in thought like an elongated pause, longer than a comma but shorter than a period. The semicolon looks like a comma with a period above it, and this can be a good way to remember what it does. The main function of a semicolon is to separate two independent clauses that deserve to be in the same sentence, but it can also be used to separate items in a list that contains commas.
Do not use semicolons too frequently. It is easy to overuse them to add sophistication when in fact it can overcomplicate your writing.
Joining Two Independent Clauses
An independent clause is another way of saying complete sentence, so if you have two complete sentences that are related to each other, they can be combined using a semicolon. Refer to the Clauses and Phrases handout to read more about different clauses.
Appropriate Usage: As Ron was driving the Ford Angelina, Harry opened a map of Great Britain; the chance of the car falling behind the Hogwarts Express was great.
The example above is using the semicolon appropriately because there are two complete sentences on either side of the semicolon, the two ideas are closely related, the extended pause helps link the ideas better together, and there is a smoother rhythm established (instead of using a period). The semicolon also builds an inferential relationship between the two ideas that would be lost without the semicolon.
Inappropriate Usage: As Ron was driving the Ford Angelina, Harry pulled out a map of Great Britain; the Scottish countryside was gorgeous in the fall.
While the example above is technically correct since both clauses on either side of the colon are independent, they do not relate closely enough without further explanation. It is unclear how Harry pulling out a map of Britain relates to the beauty outside the car. It would make more sense to use this opportunity to expand on action inside the car or explain why the map was necessary.
Tip: Test your clauses
In order to use a semicolon, each sentence on both sides of the semicolon must be able to stand alone as a complete sentence. Cover up each portion of the sentence until the semicolon, and say each part out loud. Do you know who/what the subject is? Is there a verb? Could you say this sentence to someone on the street and they could understand your meaning? If you’ve answered yes to these questions for both sides of the semicolon, then you have two independent clauses!
Combining two independent clauses with a conjunctive adverb
Sometimes a conjunctive adverb (a word like consequently, however, therefore, etc.) connects the two clauses by providing context for how the two clauses relate. The semicolon should precede this connecting word followed by a comma:
Example: Hermione received the best grades of her year; consequently, she received a well-paying job at the Ministry of Magic.
Example: Professor McGonagall was pleased Harry Potter was sorted in her house; however, she was concerned Professor Snape would dislike Harry even more.
A note about “however”: Some professors do not condone using “however” following a semicolon, so make sure you know your particular class guidelines related to style and mechanics.
Separating Lists with Commas and Semicolons
When creating a list, sometimes it is necessary to add additional information and a mini list inside the main part of the list. In these situations, offsetting all this extra information will make it confusing if the mini list or additional information is part of the main list. Adding a semicolon will provide better separation between these ideas.
Example: The panel consisted of Professor Snape, the potions master; Professor Flitwick, the charms instructor; and Professor McGonagall, the transfiguration instructor.
Example: Dolores Umbridge dislikes non-human creatures like centaurs, goblins, and giants; disorder and chaos; and Harry Potter.
In a draft the semicolon often provides a convenient link between thoughts, but in revising, you may discover that some of these linked statements ought to stand alone. Don’t be afraid to experiment with your sentence structures to play with the pacing and flow of your ideas.