The semicolon signals a more significant pause than a comma but a less significant pause than a period. Following are three common semicolon applications.
3.2.1 Between Independent Clauses
The most common use of the semicolon is as a connector between two independent clauses. For instance:
His flight was canceled; he cursed his luck.
What is the difference between the sentence above and the following example?
His flight was canceled. He cursed his luck.
The period calls for a more complete stop than the semicolon did. Use a semicolon when the relationship between the two clauses is a close one. In this example, the writer could use either the semicolon or the period, depending on his or her stylistic preferences.
3.2.2 With Conjunctive Adverbs
A particular type of adverb, known as a conjunctive adverb, sometimes appears as a transitional word between independent clauses. Examples include:
In business writing today, conjunctive adverbs are frequently punctuated incorrectly. The sentences below illustrate incorrect and correct punctuation.
The work is exciting therefore the human resources department receives many résumés.
The work is exciting therefore, the human resources department receives many résumés.
The work is exciting, therefore the human resources department receives many résumés.
The work is exciting, therefore, the human resources department receives many résumés.
The work is exciting; therefore, the human resources department receives many résumés.
The child misbehaved constantly, however his parents never reprimanded him.
The child misbehaved constantly; however, his parents never reprimanded him.
In addition to the semicolon preceding therefore and however in the correct examples above, note the comma that follows. In both of these examples, the semicolon could be replaced with a period; that choice is a stylistic one.
3.2.3 Special Case: Items in a Series
As you saw earlier, in Section 3.1.1, you should generally use a comma to separate items in a series. However, when an item in the series includes one or more commas itself, you may want to use semicolons rather than commas to separate the items. That way your reader will easily be able to identify the boundaries between them. For example:
He had written about the gas, electricity, and paper markets; the healthcare industry; and an assortment of regulatory and enforcement agencies.