A semicolon is used to join two grammatically complete clauses, which means the clauses can also be written as two separate sentences. If they cannot, then you should not use a semicolon. The semicolon is used to show that the two sentences are closely linked. If you were to use a period in place of the examples below, the text would not flow as well, even though it would be grammatically correct. The following is an excerpt from The Elements of Style. A must have for everyone, and It's only $6. If two or more clauses grammatically complete and not joined by a conjunction are to form a single compound sentence, the proper mark of punctuation is a semicolon. Stevenson's romances are entertaining; they are full of exciting adventures. It is nearly half past five; we cannot reach town before dark.